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THE DEVELOPMENT OF THE CHICK - AN INTRODUCTION TO EMBRYOLOGY  
{{Review - Lillie’s Development of the Chicken collapsetable}}
 
{| class="wikitable mw-collapsible mw-collapsed"
! Review - Lillie’s Development of the Chicken - an Introduction to Embryology 3rd Edn. (1952)  
|-
| Lillie’s Development of the Chicken Introduction to Embryology. 3rd Edition, revised by Howarp L. Hamilton. (Pp. 574; 283 figs.; 14 plates; $8.50.) New York: H. Holt & Co. 1952.
 
The writing of the present edition was begun in 1945 at the request of Dr Frank R. Lillie himself with Dr B. H. Willier acting as advisory editor. It was Dr Lillie’s hope that he might live to see the new edition in print but this was not to be. The general outline of previous editions has been preserved. Part 1, which consists of six chapters, is devoted to an account of the early embryology up to and including the 3rd day. The account of the development of the embryo is given on a general basis and in addition a detailed account is given of specially selected stages.
 
Part 2 of the book consists of nine chapters and is an account of the development of the embryo from the 4th day to hatching; the various systems and external form are described as separate entities. A few chapters, such as the one dealing with the external form of the embryo and the embryonic membranes, and the one describing the body cavities, mesenteries and septum transversum, have remained relatively unchanged. Chapter 4, ‘From laying to the formation of the first somite’, chapter 8; ‘The nervous system’, and chapter 13, ‘The urogenital system’, are more or less completely rewritten. A new chapter, the fifteenth, describing the development of the integument, has been added. The other chapters have been extensively revised.
 
The new accounts are based on recent literature, but the author has tried to follow Dr Lillie’s example of going to the chick itself to check questionable points. To this end some original work is included in the text, but it is to be regretted that the author has not indicated more clearly which parts of the text result from this original work. The only clear indications consist of an opinion on the processes concerned with the formation of endoderm (p. 101) and two footnotes, one dealing with the coelomic cavity (p. 149) and one with the tail bud (p. 176). A further footnote refers to a communication from Rawles on the patency of the ductus arteriosus in the newly-hatched chick (p. 462).
 
This book is very well written and its format is attractive. The book reaches a happy compromise which makes it a most readable introduction to embryology while yet remaining an invaluable reference work for the research worker.
 
There is little to criticize in this work which has evidently been prepared with great care, but future editions might be improved by a rearrangement of the bibliography. The references should be listed at the end of the chapter they concern and not in an appendix of 32 pages at the end of the book. Also the magnification of drawings and photographs of early embryos should be given. Figs. 153 and 155 would be improved by being photographs rather than drawings of sagittal sections through an embryo. In fig. 222 the drawings are too small and too faint.
 
Apart from these minor faults the present work is a credit to the author and had Dr Lillie lived he would have been proud to have his name associated with it. It will continue to perpetuate Dr Lillie’s influence on the development of embryology.
 
[[Embryology History - William Hamilton|W. J. Hamilton]]
 
{{chicken}}
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==THE DEVELOPMENT OF THE CHICK - AN INTRODUCTION TO EMBRYOLOGY==
BY  
BY  


Line 22: Line 46:
==Part I The Early Development To The End Of The Third Day==
==Part I The Early Development To The End Of The Third Day==


==CHAPTER XI  THE BODY-CAVITIES, MESENTERIES AND SEPTUM TRANSVERSUM==
==Appendix==


The development of these parts is one of the most difficult
subjects in embryologA^ involving, as it does, complex relations
between the viscera, vascular system, and primitive body-cavity,
on which the definitive relations of the bodv-cavities and mesenteries depend.


The pericardial and pleuro peritoneal cavities are completely
===General Literature===
separated in all vertebrates excepting Amphioxus, cyclostomes
and some Selachii and ganoids, in which narrow apertures exist
between the two. The pleural and peritoneal divisions of the
coelome of the trunk communicate widely in amphibia; among
reptiles completely closed pleural cavities are found apparently
only in Crococlilia; in birds and mammals they are completely
closed.


As we have seen, in the early embryo of the chick there is
V. Baer, C. E., L'eber Entwickelurigsgeschichte der Tiere. Beobachtung
free communication between all parts of the body-cavity. We
have to consider, therefore, (1) the separation of the pericardial
and pleuro peritoneal cavities, (2) the separation of pleural and
peritoneal cavities, and (3) development of the mesenteries.  


I. The Separation of the Pericardial and Pleuroperi
und Reflexion. Konigsbcrg, 1828 u. 1837.  
TONEAL Cavities


The pericardial cavity proceeds from the cephalic division of
id., 2. Teil — Herausgegeben von Stieda. Konigsberg, 1888.
the primitive coelome (parietal cavity of His). We may review
Duval, Mathias, Atlas d'embryologie. (With 40 plates.) Paris, 1889.  
its primitive relations as follows (stage of 10 somites; see Chap.  
Foster, M., and Balfour, F. M., The Elements of Embryology. Second Edition revised. London, 1883.
V) : it contains the heart which divides it into right and left
Gadow, Hans, Die Vogel, Bronn's Klassen und Ordniingen des Thier-Reichs, Bd. VI, Abth. 4, 1898.  
parts so long as the dorsal and ventral mesocardia persist; these,  
Handbuch der vergleichenden und experimentellen Entwickelimgslehre der Wirbeltiere. Edited by Dr. Oskar Hertwig and written by numerous  collaborators. Jena, 1901-1907.
however, disappear very early. Laterally, the parietal cavity
communicates with the extra-embryonic body-cavity (Figs. 53
and 54) ; posteriorly it is bounded by the wall of the anterior
intestinal portal (Fig. 67), on which the heart is seated like a


333


Hls, W., LTntersuchungen fiber die erste Anlage des Wirbeltierleibes. Die  erste Entwickelung des Hiihnchens im Ei. Leipzig, 1868.
Keibel, F., and Abraham, K., Normaltafeln zur Entwickelungsgeschichte  des Huhnes (Gallus domesticus). Jena, 1900.




334 THE DEVELOPMENT OF THE CHICK
V. KoLLiKER, A., Entwickelungsgeschichte des Menschen und der hoheren


rider in his saddle, the body of the rider being represented by
Thiere. Zweite Aufl. Leipzig, 1879.
the heart, and his legs by the omphalomesenteric veins. On
Marshall, A. M., Vertebrate Embryology. A Text-book for Students and  
each side of this posterior wall the parietal cavity communicates
with the coelome of the trunk. The floor of the parietal cavity
comprises two parts meeting at the head-fold, the anterior part
being composed of somatopleure, and the posterior part of
splanchnopleure; the former is part of the definitive pericardial
wall, the latter, known as the precardial plate, is provisional


(Fig! 67).
Practitioners. (Ch. IV, The Development of the Chick.) New York


The lateral mesocardia also take part in boundmg the parietal
and London, 1893.  
cavity. It will be remembered that these arise as a fusion on
MiNOT, C. S., Laboratory Text-book of Embryology. Philadelphia, 1903.  
each side between the somatopleure and the primitive omphalomesenteric veins, and that the ducts of Cuvier develop in them.  
Pander, Beitrage zur Entwickelungsgeschichte des Hiihnchens im Ei. Wiirz
As the blastoderm is spread out flat at the time that they form,  
burg, 1817.  
they constitute at first a lateral boundary to the posterior part
Prevost et Dumas, Memoire sur le developpement du poulet dans I'oeuf.  
of the parietal cavity; but as the embryo becomes separated from
the blastoderm they assume a frontal position between the sinus
venosus and body-wall, tne original median face becoming dorsal
and the lateral face ventral. Thus they come to form a dorsal
wall for the posterior part of the parietal cavity (Fig. 119). The
communication of the parietal cavity with the ccelome of the
trunk is thus divided into two, known respectively as the dorsal
parietal recess and the ventral parietal recess. The former is
a passageway above the lateral mesocardia, communicating in
front with the parietal (pericardial) cavity and behind with the
trunk cavity; the latter is a communication on each side of the
wall of the anterior intestinal portal ventral to the lateral mesocardia.  


The completion of the posterior wall of the pericardium is
Ann. Sc. Nat., Vol. XII, 1827.
brought about by the formation and development of the septum
Preyer, W., Specielle Physiologic des Embryo. Leipzig, 1885.
transversum.  
Remak, R., Untersuchungen iiber die Entwickelung der Wirbelthiere. Berlin, 1855.  


Septum Transversum. The septum transversum arises from
===Literature — Chapter I===
three originally distinct parts, viz., (1) a median mass, (2) the
lateral mesocardia, and (3) lateral closing folds arising from
the body-wall between the uml:)ilicus and the lateral mesocardia.


1. The median mass proceeds from the ventral mesentery
Bartelmez, George W., 1912, The Bilaterality of the Pigeon's Egg. A
of the fore-gut. The location of the heart and liver in the ventral
Study in Egg Organization from the First Growth Period of the Oocyte
mesentery divides it in three parts, viz., (a) a superior part,
to the Beginning of Cleavage. Journ. of Morph. Vol. 23., pp. 269-328.
comprising the mesocardium and dorsal ligament of the liver
(gastrohepatic ligament), uniting the floor of the fore-gut and


CoSTE, M., Histoire generale et particuliere du developpement des corps
organises, T. I. (Formation of Egg in Oviduct, see Chap. VI). Paris,
1847-1849.


D 'Hollander, F., Recherches sur I'oogenese et sur la structure et la signification du noyau vitellin de Balbiani chez les oiseaux. Archiv. d'anat.
micr., T. VII, 1905.


THE BODY-CAVITIES
Gegenbaur, C, Ueber den Bau und die Entwickelung der Wirbeltiereier
mit partieller Dottertheilung. Archiv. Anat. u. Phys., 1861.




Glaser, Otto, 1913, On the Origin of Double-yolked Eggs. Biol. Bull.,


335
Vol. 24, pp. 175-186.
HoLL, M., Ueber die Reifung der Eizelle des Huhnes. Sitzungsber. Akad
Wiss. Wien, math.-nat. KL, Bd. XCIX, Abth. Ill, 1890.


V. Nathusius, W., Zur Bildung der Eihiillen. Zool. Anz. Bd. XIX, 1896.


Die Entwickelung von Schale und Schalenhaut des Hiihnereies im


the heart and Uver, (h) a median portion comprising the sinus
Ovidukt. Zeitschr. wiss. Zool., Bd. LV, 1893.  
venosus, ductus venosus and Hver, and (c) an inferior portion.  
Tlie superior part persists in the region of the sinus venosus and
liver, and the inferior part only as the primary ventral ligament
of the liver.  


The median mass of the septum transversum thus includes
Parker, G. H., Double Hen's Eggs. American Naturalist, Vol. XL. 1906.  
the sinus venosus, liver, and dorsal and ventral ligaments of the
liver.  


At sixty hours the median mass includes chiefly the sinus
Pearl, Raymond and Curtis, M. R, 1912, Studies on the Physiology of
and ductus venosus and their mesenteries. At eighty hours
(Fig. 192) a constriction begins to appear between sinus and


Reproduction in the Domestic Fowl. V. Data Regarding the Physiology


of the Oviduct. Journ. of Exp. Zoology. Vol. 12, pp. 99-132.
Riddle, Oscar, 1911, On the Formation, Significance and Chemistry of the White and Yellow Yolk of Ova. Journ. of Morph., Vol. 22, pp. 455-490.


SoNNENBRODT, 1908, Die Wachstunsperiode der Oocyte des Huhns. Arch.


Fig. 192. — Reconstruction of the septum transversum and
f. mikr. Anat. w. Entw. Bd. 72, pp. 415-480.  
associated mesenteries of a chick embryo of 80 hours. (After
Waldeyer, W., Die Geschlechtszellen. Handbuch der vergl. und exper.  
Ravn.)
Ao., Aorta. Int., Intestine. Liv., Liver. PI. m'g., Plica


Entwickelungslehre der \Yirbeltiere. Bd. I, T. 1, 1901.


===Literature — Chapter II===


mesogastrica.  
Andrews, E. A., Some Intercellular Connections in an Egg of a Fowl. The
Johns Hopkins University Circular. Notes from the Biological Laboratory, March, 1907.  


Barfurth, D., Versuche iiber die parthenogenetische Furchung des Hiihnereies. Arch. Entw.-mech., Bd. 2, 1895.


Blount, Mary, The Early Development of the Pigeon's Egg with Especial
Reference to the Supernumerary Sperm-nuclei, the Periblast and the
Germ-wall. Biol. Bull., Vol. XIII, 1907.


S.V., Sinus venosus.  
Duval, M., De la formation du l^lastoderm dans Foeuf d'oiseau. Ann. Sc.
Nat. Zool., Ser. 6, T. XVIII, 1884.  


Gasser, E., Der Parablast und der Keimwall der Vogelkeimscheibe. Sitzungsber. der Ges. zur Beford. d. ges. Naturwiss. zu Marburg, 1883.
Eierstocksei und Eileiterei des Vogels. Ibid, 1884.


Gotte, a., Beitrage zur Entwickelungsgeschichte der Wirbeltiere, II. Die
Bildung der Keimblatter und des Blutes im Hiihnerei. Archiv. mikr.
Anat., Bd. X, 1874.


ductus venosus, and the walls of the latter are expanded by the
Harper, E. H., The Fertilization and Early Development of the Pigeon's
formation of liver tissue, so that the cylindrical form characteristic of sixty hours is lost, and the lateral walls of the ductus
Egg. Am. Jour. Anat., Vol. Ill, 1904.  
venosus bulge considerably. The continued growth of the liver
causes a rapid lateral expansion of this portion of the septum
transversum (Fig. 193 A).  


The primary ventral ligament of the liver is included within
KiONKA, H., Die Furchung des Hiihnereies. Anat. Hefte, Bd. Ill, 1894.
the wall of the anterior intestinal portal up to al)out eighty hours.  
But, as the volk-sac shifts farther back, this ligament appears
as a separate membrane (inferior part of the primary ventral


Lau, H., Die parthenogenetische Furchung des Hiihnereies. Inaug. Dissert.
Jurjew — Dorpat., 1894.


Oellacher, J., Untersuchungen iiber die Furchung und Blatterl)ildung im
Hiihnerei. Studien iiber experimentelle Pathologic von Strieker, Bd


336
I, 1869.
Oellacher, J., Die Veranderungen des unbefruchteten Keimes des Huhnereies
im Eileiter und bei Bebriitungsversuchen. Zeitschr. wiss. Zool., Bd.
XXII, 1872.




Patterson, J. Thomas, Gastrulation in the Pigeon's Egg; a ^Morphological


THE DEVELOPMENT OF THE CHICK
and Experimental Study. The Journ. of Morph., Vol. 29, pp. 65-123,


1909.
Patterson, J. Thomas, Studies on the Early Dev^elopment of the Hen's


Egg. 1. History of the Early Cleavage and of the Accessory Cleavage.


The Journ. of Morph., Vol. 21, pp. 101-134, 1910.
Rauber, a., Ueber die Stellung des Hiihnchens im Entwicklungsplan.


Fig. 193. — Reconstruction of the septum transversum and
Leipzig, 1876.  
associated mesenteries of a chick embryo of 5 to 6 days. (After
Sobotta, J., Die Reifung und Befruchtung des Wirbeltiereies. Ergeb.  


Ravn.)
Anat. u. Entwickelungsgesch., Bd. V, 1895.  


A. Entire.
===Literature — Chapter III===


B. After removal of the liver and sinus venosus.
Edwards, C. L., The Physiological Zero and the Index of Development for


A., Aorta, ac. M., Accessory mesentery. cav. F., Caval
the Egg of the Domestic Fowl, Gallus Domesticus. Am. Journ. Physiol.,  
fold. coel. F., Coeliac fold. Her., Hiatus communis recessum. Int., Intestine. Lg., Lung. Liv., Liver, m. p., Pleuropericardial membrane, pvl., Primary ventral ligament of the
hver. Sv., Sinus venosus.


mesentery), uniting the ventral and posterior face of the liver
Vol. VI, 1902.
Eycleshymer, a. C, Some Observations and Experiments on the Natural


to the body-wall just in front of the umbilicus (Fig. 193 A, pvl.).  
and Artificial Incubation of the Egg of the Common Fowl. Biol. Bull.,


For the purposes of these figures the body-wall is cut away.  
Vol. XII, 1907.
Fere, Cm., Note sur I'influence de la temperature sur I'incubation de I'oeuf


Nevertheless, it can be seen that the pericardial cavity commiuii
de poule. Journ. de I'anatomie et de la physiologic, Paris, T. XXX,  


1894.


THE BODY-CAVITIES 337
===Literature — Chapter IV and V===


cates with the peritoneal cavity around the median mass of the
septum transversum beneath the kiteral mesocardia.


2. The lateral mesocardia constitute the second component
Assheton, R., An Experimental Examination into the Growth of the Blastoderm of the Chick. Proc. Roy. Soc, London, Vol. LX, 1896.  
of the septum transversum. At the stage of sixty hours they
are nearly round in section. At eighty-six hours the substance
posterior to the duct of Cuvier begins to thicken (Fig. 192) so
that the section is no longer round but elongated towards the
umbilicus. They still extend almost transversely to the lateral
body-wall. However, the retreat of the heart backwards soon
changes their direction (Fig. 193 A) so as to form a long oblique
partition between the pericardium and the dorsal parietal recess,  
the direction of the ducts of Cuvier being changed at the same
time. The lateral mesocardia are directly continuous with the
anterior portion of the median mass of the septum transversum.  


3. The lateral closing folds arise as ridges of the lateral bodywall extending obliquely from the primary ventral ligament of  
Balfour, F. M. The Development and Growth of the Layers of the Blastoderm. Quar. Jour. Micr. Sc, Vol. XIII, 1873.  
the liver upwards and forwards to the lateral mesocardia. They
arise along the course of the umbilical veins which open at first
into the ducts of Cuvier. As the lateral closing folds develop
first at their anterior ends, they appear as direct backward
prolongations of the lateral mesocardia. They fuse with the
lateral ventral surface of the liver (median mass of the septum
transversum), and when they are completed back to the primary
ventral ligament of the liver, they completely close the ventral
communication of the pericardium with the peritoneal cavity.  
They mark out a triangular area on the cephalic face of the liver
with postero-ventral apex and antero-dorsal base, which forms
the median portion of the posterior wall of the pericardium (cf.  
Fig. 193 A). At six days the ventral communication of the
pericardium is reduced to a very small opening, and at eight days
it is entirely closed.  


Closure of the Dorsal Opening of the Pericardium. As already
On the Disappearance of the Primitive Groove in the Embryo Chick.  
noted the pericardial cavity communicates with the peritoneal
lUd.  
cavity above the lateral mesocardia by way of the dorsal
parietal recesses, which are destined to form a large part of the  
pleural cavities. We have, therefore, to consider next the closure
of the aperture between the pleural and pericardial cavities.  
We have already seen that the heart shifts backwards very rapidly
between the third and sixth days, and this draws out the lateral
mesocardia in an oblique plane directed from dorsal anterior to


Balfour, F. M., and Deighton, A Renewed Study of the Germinal Layers
of the Chick. Quar. Jour. Micr. Sc, Vol. XXII, 1882.


DissE, J., Die Entwickelung des mittleren Keimblattes im Hiihnerei. Arch,
mikr. Anat., Bd. XV, 1878.


338 THE DEVELOPMENT OF THE CHICK
DuRSY, Emil, Der Primitivstreif des Hiihnchens. Lahr, 1866.


ventral posterior (Fig. 193); the ducts of Ciivier thus become
Duval, Mathias, Etudes sur la hgne primitive de rembr3'on du poulet.  
oblique also, and the lateral mesocardia become converted into
Ann. Sc. Nat. Zool., Ser. 6, T. VII, 1S7S.  
an oblique septum between the posterior parts of the incipient
pleural cavities and the pericardial cavity (pleuro-pericardial
membrane). In front of the sinus venosus, however, the pleural
and pericardial cavities communicate with one another between
the ducts of Cuvier, which form a projection from the lateral
body-wall, and the bronchi which project laterally beneath the
oesophagus. These apertures are gradually closed by fusion of
the walls of the bronchi with the projecting duct of Cuvier, beginning in front and extending back to the sinus venosus. Thus the
incipient pleural cavities come to end blindly in front, though
they still communicate widely behind with the peritoneal cavity.
The membrane thus established between pleural and pericardial
cavities is know^n as the pleuro-pericardial membrane.  


Establishment of Independent Pericardial Walls. With the
De la formation du blastoderm dans I'oiuf d'oiseau. Ann. Sc. Nat.  
formation of the ventral body-wall the precardial plate (a portion
Zool., Ser. 6, T. XVIII. Paris, 1884.  
of the splanchnopleure, which at first forms part of the floor of
the pericardial cavity) is gradually replaced by the ventral bodywall. The pericardial cavity is thus bounded ventrally and
laterally by the body-wall and posteriorly by the median mass
of the septum transversum. It has no independent walls at
first. The definitive pericardium is, however, a membranous
sac, and this is formed by two main processes: in the first place
the membrane of the anterior face of the liver (median mass of
the septum transversum) which forms the posterior boundary
of the pericardium becomes much thickened, and gradually
splits off from the liver (cf. Figs. 148 and 150), the peritoneal
cavity extending pari passu between the liver and the membrana
pericardiaco-peritoneale thus formed. The suspensory ligament
of the liver, however, remains in the middle line, and the membrane is also directly continuous w^ith the liver dorsally around
the roots of the great veins. Thus a membranous wall is established for the posterior part of the pericardium. In the second
place the peritoneal cavity extends secondarily into the bodywall bounding the pericardium ventrally and laterally, and thus
splits a membranous pericardial sac oE from the body-wall. In
this process the liver appears to play an active role. At least
its anterior lobes occupy the peritoneal spaces thus established
(Fig. 194). In the mammals, on the other hand, it is the ex


Evans, Herbert M. On the Development of the Aorta), Cardinal and
UmbiUcal Veins and other Blood-vessels of Vertebrate Embryos from
Capillaries. Anatomical Record., Vol. 3, pp. 498-518, 1909.


THE BODY-CAVITIES
Fol, H., Recherches sur le developpement des protovertcbres chez I'embryon
du poulet. Arch. sc. phys. et nat. Geneve, T. II, 1884.


Gasser, Lieber den Primitivstreifen bei Vogelembryonen. Sitz.-Ber. d. Gcs.
z. Beforcl. d. ges. Naturw. z. Marburg, 1877.


 
Der Primitivestreif bei Vogelembryonen (Huhn w. Gans). Schriften
339
d. Ges. z. Beford. d. ges. Naturw. z. Marburg, Bd. XI, Suppl. Heft 1,
1879.




Gasser, Beitrage zur Kenntnis der Vogelkeimscheibe. Arch. Anat. u


tension of the pleural cavities ventrally that splits the membranous pericardium from the body-wall.  
Entw., 1882.  


Derivatives of the Septum Transversum. From the preceding
Der Parablast unci der Keimwall der Vogelkeimscheibe. Sitz.-Ber.  
account it will be seen that the following are derivatives of the
septum transversum: (1) The posterior part of the pericardial
membrane. (2) The pleuro-pericardial membrane. (3) The liver
with its vessels and gastro-hepatic and primary ventral ligaments.  


d. Ges. z. Beford. d. ges. Naturw. z. Marburg, 1883.
GoETTE, A., Beitrage zur Entwickelungsgeschichte der Wirbeltiere. II.


Die Bildung der Keimblatter und des Blutes im Hiihnerei. Arch. mikr.


Anat., Bd. X, 1874.
Hertwig, O., Die Lehre von den Keimblattern. Handbuch der vergl. und


Fig. 194. — Photot;raph of a transverse section of an 8-day chick.  
exper. Entwickehuigslehre der Wirbeltiere. Vol. I. Jena, 1903.
His, W., Der Keimwall des Htihnereies und die Entstehung der para
blastischen Zellen. Arch. Anat. und Entw., Bd. I, 1876.  


abd. A. S., Abdominal air-sac. A. coel., Coeliac artery. Ao., Aorta.
Neue Untersuchung liber die Bildung des Hiihnerembryo. Arch.  
A. o. m., Omphalomesenteric artery. Aiir. d., Right auricle. Cav. pc,
Pericardial cavity. M. D., Miillerian duct. M. pc, Membranous pericardium. Msn., Mesonephros. Pr'v., Proventriculus. S., Septum ventriculorum. V. c. i., Vena cava inferior. V. h. d., Right hepatic vein. V. d.,
Right ventricle. V. s., Left ventricle.  


(4) A small part of the heart (the sinus venosus). As regards
Anat. und Entw., 1877.
the last, it should be noted that the anterior portion of the original
septum transversum is gradually constricted from the major
posterior portion and becomes established as the sinus venosus;


Lecithoblast und Angioblast der "Wirbelthiere. Histogenetische


Studien. Abh. der math.-phys. Klasse der Konigl. Sachs. Ges. der


340 THE DEVELOPMENT OF THE CHICK
Wissenschaften, Bd. XXVI. Leipzig, 1900.


this subsequently becomes incorporated in the right auricle of
Die Bildung der Somatopleura und der Gefasse beim Hiihnchen.  
the heart. (See Chap. XII).  


II. Separation of Pleural and Peritoneal Cavities; Origin
Anat. Anz., Bd. XXI, 1902.
OF THE Septum Pleuro-peritoneale
Hubbard, M. E., Some Experiments on the Order of Succession of the


The pleuro-peritoneal septum arises from the so-called accessory mesenteries, the origin of which must now be described.  
Somites of the Chick. Am. Nat., Vol. 42, pp. 466-471, 1908.  
At first the septum transversum has only a median dorsal mesentery, viz., the superior part of the primary ventral mesentery
Janosik, J., Beitrag zur Kenntnis des Keimwulstes bei Vogeln. Sitz-Ber
that unites the septum transversum to the floor of the fore-gut,  
Akad. Wiss. Wien, math.-phys. KL, Bd. LXXXIV, 1882.  
and so by way of the dorsal mesentery of the latter to the dorsal
Roller, C, Beitrage zur Kenntnis des Hiihnerkeimes im Beginne der Be
body-wall. Subsequently, however, there arises a pair of mesenteries extending from the lateral wall of the cesophagus to the
briitung. Sitzungsber. Wien. Akad. Wiss., math.-nat. KL, 1879.
septum transversum. These are the accessory mesenteries, and
Untersuchungen liber die Blatterbildung im Hlihnerkeim. Arch.  
they arise as follows: about the sixtieth hour they appear as
mesenchymatous outgrowths, forming elongated lobes, projecting
from the side walls of the oesophagus opposite the hind end of
the lung rudiments. The right and left lobes are practically
the same size at first and they bend over ventrally and soon fuse
with the median mass of the septum transversum, represented
at this time by the sinus and meatus venosus (cf. Figs. 118-120,  
Chap. VI). Thus are produced a pair of bays of the peritoneal
cavity ending blindly in front, bounded laterally by the accessory
mesenteries, and in the median direction by the intestine and
its mesenteries. These are the pneumato-enteric recesses.  


These bays have received different names from the various authors:
mikr. Anat., Bd. XX, 1881.
thus His named only the right one as recessus superior sacci omenti;
V. Kolliker, a., Zur Entwickelung der Keimblatter im Hiihnerei. Verb.  
the left one being practically absent in mammals; Stoss called both recessus pleuro-peritoneales ; :\Iall called them gastric diverticula; Hochstetter, recessus pulmo-hepatici ; Maurer, bursa hepatico-enterica ; Ravn,  
recessus superior for the right one and recessus sinister for the left. We
may call them the pneumato-enteric recesses (recessus pneumato-enterici) ,  
following Broman.  


At seventy-two hours the entodermal lung-sacs extend to
phys.-med. Ges. Wlirzburg, Bd. VIII, 1875.  
the base of the accessory mesenteries, ending at the anterior
KopscH,FR.,Ueber die Bedeutung des Primitivstreifens beim Hiihnerembryo,  
end of the pneumato-enteric recesses. On the left side at this
time the recess is fully formed back to near the anterior end of
the cephalic hepatic diverticulum, on the right side considerably
farther back; that is, the accessory mesentery is already longer
on the right than on the left side, and the mesenchymatous lobe


und liber die ihm homologen Theile bei den Embryonen der niederen


Wirbeltiere. Intern. Monatschr. f. Anat. u. Phys., Bd. XIX, 1902.
MiTROPHANOW, P. J., Teratogene Studien. II. Experimentellen Beo
bachtungen liber die erste Anlage der Primitivrinne der Vogel. Arch.


THE BODY-CAVITIES 341
Entw.-mech., Bd. VI, 1898.


from which it arises (pUca mesogastrica, Broman) can be traced
Beobachtungen liber die erste Entwickelung der Vogel. Anat.  
back, shifting its attachment to the dorsal mesentery, as far as
the anterior intestinal portal and a little farther (Fig. 192, cf.
also Fig. 120).  


At ninety-six hours the entodermal lung-sacs extend far into
Hefte, Bd. XII, 1899.
the accessory mesenteries, and thus lie laterally to the pneumatoenteric recesses. On the left side the accessory mesentery ceases
Now^\cK, K., Neue Untersuchungen liber die Bildung der beiden primiiren
opposite the tip of the lung, but on the right side it is continued
back by the mesentery of the vena cava as far as the middle of
the stomach, and in this region its ventral attachment is to the
superior lateral angle of the liver.  


The growth of the lung-sacs into the accessory mesenteries
Keimblatter und die Entstehung des Primitivstreifen beim Hiihnerembryo. Inaug. Diss. Berlin, 1902.  
divides the latter into three parts, viz., a superior portion uniting
Patterson, J. Thos., The Order of Appearance of the Anterior Somites in
the lung to the dorsal mesentery, a median portion enclosing the
lung, and an inferior portion uniting the lung-sacs to the median
mass of the septum trans versum. Now, as the liver expands
laterally the ventral attachment of the accessory mesentery is
carried out towards the lateral body-wall, inasmuch as its attachment is to the lateral superior face of the liver (cf. Fig. 231, Chap.
XIII). Thus the accessory mesenteries are gradually shifted
from their original almost sagittal plane to a plane that is approximately frontal. The developing lungs project dorsally from the
accessory mesenteries, which may now be called the pleuroperitoneal membranes, into the pleural cavities (Fig. 189); and
the latter communicate with the peritoneal cavity onl}^ laterally
to the liver. These communications are then soon closed by a
fusion betw^een the lateral edges of the pleuro-peritoneal membrane and the lateral body-wall; this fusion is not completely
established on the eighth day, but it is on the eleventh day.


In reptiles and mammals the so-called mesonephric mesentery plays
the Chick. Biol. Bull., Vol. XIII, 1907.
an important part in the closure of the pleural cavities. It arises from
Patterson, J. T. An experimental Study on the Development of the Vascular
the apex of the mesonephros at its cephalic end, and fuses with the septum
transversum. It thus forms a partition between the hinder portion
of the pleural cavity and the cranio-lateral recesses of the peritoneal
cavity. Subsequently, in mammals, its posterior free border fuses with
the caudal bounding folds of the pleural cavity that arise as forwardly
directed projections from the accessory mesentery on the right side
and the wall of the stomach on the left. Hochstetter states that such
a mesonephric fold is found in the chick but that it does not appear to
play any essential part in the formation of the septum pleuro-peritoneale.


Area of the Chick Blastoderm. Biol. Bull. XVI, pp. 83-90, 1909.
Peebles, Florence. Some Experiments on the Primitive Streak of the


Chick. Arch. Entw.-mech., Bd. VII, 1898.


342 THE DEVELOPMENT OF THE CHICK
A Prehminary Note on the Position of the Primitive Streak and its


I find it in the chick as a very minute vestige at the cranial end of the  
Relation to the Embryo of the Chick. Biol. Bull., Vol. IV, 1903.  
mesonephros associated with the funnel of the Miillerian duct. It aids
in the final closure of the pleural cavity by bridging over the narrowchink between the lateral angle of the pleuro-peritoneal membrane and
the lateral body-wall. (See Bertelli, 1898.)


The oblique septum of birds arises as a layer split off from
the septum pleuro-peritoneale (pulmonary aponeurosis or pulmonary diaphragm of adult anatomy) by the expansion of the
anterior and posterior thoracic air-sacs within it. This mode
of formation is clearly seen, particularly on the right side, in a
series of transverse sections of a chick embryo of eleven days
(Fig. 190). Thus the cavity between the oblique septum and the
pulmonary diaphragm (cavum sub-pulmonale of Huxley) is not
a portion of the bodv-cavitv and bears no relation to it. The
ingrowth of muscles into the pulmonary diaphragm can be
observed in the same series of sections. It begins on the tenth
day according to Bertelli.


HI. The Mesenteries


The dorsal mesentery is originally a vertical membrane
Peebles, Florence, The Location of the Chick Embryo upon the Blastoderm. Journ. Exp. Zool., Vol. I, 1904.  
formed by reduplication of the peritoneum from the mid-dorsal
Platt, J. B., Studies on the Primitive Axial Segmentation of the Chick.
line of the body-cavity to the intestine; mesenchyme is contained
from the outset between its peritoneal layers, and serves as the
pathway for the development of the nerves and blood-vessels
of the intestine. In the course of development, its lower edge
elongates with the growth of the intestine, and is thrown into
folds, or twisted and turned with the various folds and turnings
of the intestine. Detailed studies of its later development in the
chick have not been published, but the principal events in its
history are as follows: For convenience of description the dorsal
mesentery may be divided into three portions corresponding to
the main divisions of the alimentary tract, viz., an anterior
division belonging to the stomach and duodenum, sometimes
known as the mesogastrium; an intestinal division belonging to
the second loop of the embryonic intestine that descends into
the umbilicus; and a posterior division belonging to the large
intestine and rectum. Inasmuch as the duodeno-jejunal flexure
(Figs. 179 and 180, X) retains from an early stage a short
mesenterial attachment, there is quite a sharp boundary in the
chick between the first and second divisions of the dorsal


Bull. Mus. Comp. Zool. Harv., Vol. 17, 1889.
Rabl, C, Theorie des Mesoderms. Morph. Jahrb., Bde. XV und XIX,


1889 and 1892.
Rauber, a., Primitivstreifen und Neurula der Wirbelthiere, in normaler


THE BODY-CAVITIES 343
und pathologischer Beziehung. Leipzig, 1877.


mesentery. The mesogastriiim becomes modified b}- the displacement of the stomach, the outgrowth of the duodenal loop,
Ueber die embryonale Anlage des Hiihnchens. Centralb. d. med.  
the formation of the omentum, and by the development of the
pancreas and spleen in it. (See below.)


The second division of the mesentery is related to the longest
Wiss., Bd. XII, 1875.  
division of the intestine, but as this arises from a relatively very
small part of the embryonic intestine, its dorsal attachment is
short and the roots of the mesenteric arteries are grouped
together. The third division is relatively long and not very
deep; at its base it approaches near to the mesogastrium, to
which it is attached by the root of the intermediate division.  


The Origin of the Omentum (mainly after Broman). In a
Ueber die erste Entwickelung der Vogel und die Bedeutung der Primi
preceding section we saw that the accessory mesentery is continued back on the right side (at the stage of seventy-two hours)
tivrinne. Sitz.-ber. d. naturf. Ges. zu Leipzig, 1876.
by a fold of the dorsal mesentery of the stomach known as the
Rex, Hugo, Ueber das Mesoderm des Vorderkopfes der Ente. Archiv. mikr. Anat., Bd. L., 1897.  
plica mesogastrica (Fig. 120). The stomach is already displaced
somewhat to the left, hence the dorsal mesentery is bent also,
and the plica mesogastrica arises from the angle of the bend
(Fig. 120). The ventral mesentery of the stomach, including
the meatus venosus and liver, remains in the middle line. Thus
the bodv-cavitv on the right of the stomach is divided into two
main divisions, viz., the general peritoneal cavity lateral to the
plica mesogastrica and liver, and another cavity between the
plica mesogastrica and liver on the one hand, and the stomach
on the other; the latter cavity has two divisions, a dorsal one
between the plica mesogastrica and upper half of the stomach
(recessus mesenterico-entericus) and a ventral one between the
liver (meatus venosus) and stomach (recessus hepatico-entericus),
which are continued anteriorly into the pneumato-enteric recesses.  
Subsequently, they Ijecome entirely shut off from the peritoneal
cavity, but at present (stage of Fig. 120) they communicate
with it by a long fissure bounded by the accessory mesentery in
front, by the plica mesogastrica above, and the meatus venosus
below; this opening may be called the hiatus communis recessum;
it corresponds to the foramen of Winslow of mammals (cf. Fig.  
193 A).  


As development proceeds, a progressive fusion of the right
dorsal border of the liver with the plica mesogastrica takes place
in a cranio-caudal direction, thus lessening the extent of the^
hiatus.


RiiCKERT, J., Entwickelung der extra-embryonalen Gefasse der Vogel. Hand
buch der vergl. w. exp. Entw.-lehre der Wirbelthiere, Bd. I, T. 1,


1906.


344 THE DEVEL0P:\IEXT OF THE CHICK
Ueber die Abstammung der bluthaltigen Gefassanlagen beim Huhn,


At about ninety-six hours, the pUca mesogastrica divides to
und uber die Entstehung des Randsinus beim Huhn und bei Torpedo.  
form two longitudinal folds, in the lateral one of which the vena
cava inferior develops (cf. Fig. 193 B) ; it is hence known as the
caval fold; the more median division is the coeliac fold including
the coeliac arter}^ Between them is a subdivision of the recesses
known as the cavo-coeliac recess, which corresponds to the atrium
burs£e omentalis of mammals. The fusion of the right lateral
border of the liver continues along the course of the caval fold,
and the vena cava inferior is soon completely enveloped in liver
tissue. Behind the point where the vena cava inferior enters
the liver, the latter fuses with the ventral edge of the right mesonephros, thus progressively diminishing the opening of the collective recesses into the peritoneal cavity. At about the one hundred and sixtieth hour, the fusion reaches the portal vein, and the
recesses are thus completely shut off from the peritoneal cavity.
Thus a lesser peritoneal cavity is completely separated on the
right side of the body from the main cavity; and from the former
both lesser and greater omental spaces develop on the right and
left sides respectively of the coeliac fold. (Bursa omenti minoris
and bursa omenti majoris of the bursa omentalis dextra.)


The communication of the lesser and greater omental spaces
Sitzungsber. der Bay. Akad. Wiss., 1903.
in front of the coeliac fold is closed by fusion of the latter with
ScHAUiNSLAND, H., Bcitrage zur Biologie und Entwickelung der Hatteria
the right side of the proventriculus at about the one hundred
and sixtieth hour, though it remains open throughout life in some
birds. The two omental spaces are also elongated in a posterior
direction by the caudal prolongation of the right lobe of the liver
and of the gizzard respectively (Fig. 195). The lateral wall of
the omentum minus is attached to the lateral dorsal border of
the right lobe of the liver as already described, and it is therefore
carried back by the elongation of this lobe; but as the vena cava
inferior is inserted about the middle of this wall and cannot be
drawn back, it results that there is a deep median indentation
of the lateral wall of the omentum minus, at the bottom of which
lies the vena cava inferior.


The condition of both right and left omental spaces at 154
nebst Bemerkungen uber die Entwickelung der Sauropsiden. Anat.  
hours is shown in Figures 195 and 196. Subsequently, about the
eleventh day, the mesogastrium behind the spleen becomes perforated, and the greater omental space thus opens secondarily
into the left side of the body-cavity. A true omental fold exists
only for a short time in the development of the chick, and is


Anz. XV, 1899.
ViALLETOX, Developpement des aortes chez I'embryon de poulet. Journ.


de I'^nat. T. XXVIII, 1892. See also Anat. Anz., Bd. VII, 1892.
ViRCHOW, H., Der Dottersack des Huhns. Internat. Beitrage zur wiss.


THE BODY-CAVITIES
Med., Bd. I, 1891.
Waldeyer, W., Bemerkungen uber die Keimblatter und den Primitivstreifen


bei der Entwickelung des Huhnerembryo. Zeitschr. rationeller Medicin,


1869.
Whitman, C. O., A Rare Form of the Blastoderm of the Chick and its Bearing


345
on the Question of the Formation of the Vertebrate Embryo. Quar.


Journ. Micr. Sc, Vol. XXIII, 1883.
WiLLL\MS, Leonard W. The Somites of the Chick. Am. Journ. of Anat.,


Vol. 11, pp. 5.5-100, 1910.


soon taken up by the caudal elongation of the stomach. Obliteration of the cavity of the omentum by fusion of its walls takes
Literature to Chapter VI included in following chapters.  
place at its caudal end. (Broman.)


Spaces corresponding to the omental cavities are also formed
===Literature — Chapter VII===
on the left side of the body, but they are of much less extent.
(See Fig. 196.) The communication of these spaces with the
greater peritoneal cavity is not, however, shut ofT as on the right
side. However, a secondary and later fusion of the left lobe
of the liver with the lateral body-wall, and of the gizzard with




CHARBONNEiy-SALLE ct Phisalix, De I'evolution postembryonnaire du


sac vitellin chez les oiseaux. C. R. Acad. Sc, Paris, 1886.
Dareste, C, Sur I'absence totale de I'amnios dans les embryons de poule.


-rBr
C. R. Acad. Sc, Paris, T. LXXXVIII, 1879.
Duval, M., Etudes histologiques et morphologiques sur les annexes des


embryons d'oiseau. Journ. de I'anat, et de la phys., T. XX, 1884.
Etude sur I'origine de Tallantoide chez le poulet. Rev. sc. nat.,


Paris, 1877.


Doniin


Duval, M., Sur ime organe placentoide chez rembryon des oiseaux. C. R.


Acad. Sc, Paris, 1884.
Fromann, C, Ueber die Struktur der Dotterhaut des Huhnes. Sitz.-ber.


Her-
Jen. Ges. Medizin u. Naturw., 1879.
FuLLEBORN, F., Beitrage zur Entwickelung der Allantois der Vogel. Diss.,


Berlin, 1894.
Gasser, E., Beitrage zur Entwickelungsgeschichte der Allantois, der Miiller
schen Gange iind des Afters. Frankfurt a. M., 1874.
GoTTE, A., Beitrage zur Entwickelungsgeschichte des Darmkanals im Hiihn
chen. Tubingen, 1867.
HiROTA, S., On the Sero-amniotic Connection and the Foetal Membranes in


the Chick. Journ. Coll. Sc. Imp. Univ. Japan, Vol. VI, Part IV, 1^94.
LiLLiE, Frank R., Experimental Studies on the Development of the Organs


Du
in the Embryo of the Fowl (Gallus domesticus): 1. Experiments on the


Amnion and the Production of Anamniote Embryos of the Chick. Biol.


Bull., Vol. V, 1903. 2. The Development of Defective Embryos and


-Giz
the Power of Regeneration. Biol. Bull., Vol. VII, 1904.
Mertens, H., Beitrage zur Kenntniss der Fotushiillen im Vogelei. Meckels


Archiv, 1830.
Mitrophanow, p. J., Note sur la structure et la formation de I'enveloppe


du jaune de I'ceuf de la poule. Bibliogr. Anat., Paris, 1898.
PopoFF, Demetrius, Die Dottersackgefasse des Huhnes. Wiesbaden, 1894.
Pott, R., and Preyer, W., Ueber denGaswechsel und die chemischen Verander
ungen des Hiihnereies wahrend der Bebriitung. Archiv. ges. Phys., 1882.
Preyer, W., Specielle Physiologic des Embryo. Leipzig, 1885.
Ravn, E., Ueber die mesodermfreie Stelle in der Keimscheibe des Huhner
embryo. Arch. Anat. u. Entw., 1886.


-Bomd/'
Ueber den Allantoisstiel des Hiihnerembryo. Verh. Anat. Ges., 1898.
ScHAUiNSLAND, H., Die Entwickelung der Eihaute der Reptilien und der


Vogel. Handbuch der vergl. und exp. Entw.-lehre der Wirbeltiere. Bd.


I, T. 2, 1902.


Fig. 195. — Recon.struction of the omental space of a chick embryo of 154
Beitrage zur Entwickelungsgeschichte der Wirbeltiere. II. Beitrage zur


hours from the right side. (After Broman.)
Entwickelungsgeschichte der Eihaute der Sauropsiden. Bibliotheca


Bomaj., Bursa omenti majoris. Bomin., Bursa omenti minoris. Du.,
Zoologica, 1903.  
Duodenum. Giz., Gizzard. Her., Hiatus communis recessum. oe., (Esophagus, rBr., Right bronchus. Rpedx., Right pneumato-enteric recess.  
Schenk, S. L., Beitrage zur Lehre vom Amnion. Archiv. mikr. Anat., Bd.  


VII, 1871.


Ueber die Aufnahme des Nahrungsdotters wahrend des Embryonal
lebens. Sitz.-ber. Akad. Wiss. Wien, math.-nat. Kl., 1897.
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the ventral body-wall does isolate a portion of the peritoneal
Chick. Journ. of Anat. and Phys., Vol. XXIV, 1889.
cavity from the remainder on the left side. Into this the pneumato- and hepato-enteric cavities of the left side open; however,  
Soboleff, Die Verletzung des Amnions wahrend der Bebriitung. Mittheil,
it is obvious that this space is not analogous to the omental
spaces on the right.  


Origin of the Spleen. The spleen arises as a proliferation from
embryolog. Inst., Wien, 1883.
the peritoneum clothing the left side of the dorsal mesentery
Strahl, H., Eihaute und Placenta der Sauropsiden. Ergeb. Anat. u. Entw.
just above the extremity of the dorsal pancreas. This proliferation forms the angle of a cranio-caudal fold of the dorsal mesentery which is caused by the displacement of stomach and intestine
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im Bereiche des Dottersackes. Virchow's Arch., Bd. LXII, 1874.


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THE DEVELOPMENT OF THE CHICK
Das Dotterorgan der Wirbeltiere. Zeitschr. wiss. Zool., Bd. LIII,
Suppl., 1892.


Das Dotterorgan der Wirbelthiere. Arch. mikr. Anat., Bd. XL, 1892.
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to the left side of the body-cavity (Fig. 188), and which is
Mem. soc. biol., Paris, 1858.  
exaggerated by the rapid growth of the dorsal pancreas (Choronschitzky). The spleen is thus genetically related to the wall of
Weldox, W. F. R., Prof, de Vries on the Origin of Species. (Includes experiments on amnion.) Biometrica, Vol. I, 1902.  
the great omentum, and lies outside the cavity of the latter.  
The cells of the spleen are proliferated from a peritoneal thickening, which may be compared in this respect to the germinal
epithelium. It is recognizable at ninety-six hours, and the mass
formed by its proliferation grows rapidly, forming a very considerable projection into the left side of the body-cavity above
the stomach, at six days (cf. Fig. 197).  


===Literature — Chapter VIII===


Beard, J., Morphological Studies, II. The Development of the Peripheral


Rpesi)i
Nervous System of Vertebrates. Pt. I. Elasmobranchs and Aves.


Quar. Journ. Micr. Sc, Vol. XXIX, 1888.
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Brandis, F., Untersuchungen iiber das Gehirn der Vogel. Arch. mikr.


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Du-^^_
Outside the Animal Body, with Special Reference to the Nervous System.


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Cajal, S. R. y., Sur I'origine et les ramifications des fibres nerveuses de la


moelle embryonnaire. Anat. Anz., Bd. V, 1890.


R/ie>-iii
A quelle epoque aparaissent les expansions des cellules nerveuses de


la moelle epiniere du poulet. Anat. Anz., Bd. V, 1890.
Froriep, a., Ueber Anlagen von Sinnesorganen am Facialis, Glossopha
ryngeus und Vagus, iiber die genetische Stellung des Vagus zum Hypo
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u. Entw., 1885.
Carpenter, Frederick Walton, The Development of the Oculomotor Nerve,


— Bomaj
the Ciliary Ganglion, and the Abducent Nerve in the Chick. Bull.


Mus. Comp. Zool. Harv. Vol. XLVIII, 1906.
DissE, J., Die erste Entwickelung des Riechnerven. Anat. Hefte, Abth. I,


Bd. IX, 1897.
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Fig. 196. — The same model from the left side. (After Broman.)
Anat. Anz., Bd. V, 1890.  
Hrpesin., Hiatus recessus pneumato-entericus sinister. 1. Br.,
GoRONOwiTscH, N., Die axiale und die laterale (A. Goette) Kopfmetamerie
Left bronchus. Pr'v., Proventriculus. Rhesin., Recessus hepatoentericus sinister. Rpesin., Right pneumato-enteric recess. Other
abbreviations as in Fig. 195.  


According to Choronschitzky, the peritoneal cells invade the
der Vogeleml^ryonen. Anat. Anz., Bd. VII, 1892.  
neighboring mesenchyme, and, spreading through it, form an illdefined denser area, the fundamental tissue of which is therefore
mesenchymal. The meshes of the latter are in immediate continuity with the vena lienalis, but the vascular endothelium is


L'ntersuchungen iiber die Entwickelung der Sogenannten " Ganglien
leisten " im Kopfe der Vogelembryonen. Morph. Jahrb., Bd. XX, 1893.




THE BODY-CAVITIES


Heinrich, Georg, Untersuchungen iiber die Anlage des Grosshirns beim
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347
Vertebrate Head. Zool. Jahrbucher, Abth. Anat. Bd. XIII, 1900.
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phys. med. Ges. zu Wiirzburg, 1890.
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not continued into these meshes. Thus free embryonic cells
vergl. und exp. Entwickelungslehre der Wirbeltiere, Kap. VIII, IP, 1905.  
of the primordium of the spleen enter the venous circulation
Lewis, M. R. and Lewis, W. H., The Cultivation of Tissues from Chick
directly, and become transformed into blood-corpuscles.  


On account of the intimate relation between the pancreas and spleen
Embroyos in Solutions of NaCl, CaCl2, KCl and NaHCOg. Anatomical
in early embryonic stages, certain authors (see esp. Woit) have asserted
a genetic connection, deriving the spleen from the pancreas. There
is, however, no good evidence that the relation is other than that of
propinquity.  


Record, Vol. 5, pp. 277-293. See also Anat. Rec, Vol. 6, nos. 1 and 5, 1911.
Marshall, A. M., The Development of the Cranial Nerves in the Chick.


Quar. Journ. Micr. Sc, Vol. XVIII, 1878.


' Gon.  
The Segmental Value of the Cranial Nerves. Journ. Anat. and Physiol.,


Vol. XVI, 1882.
v. MiHALCOVics, v., Entwickelungsgeschichte des Gehirns. Leipzig, 1877.
Onodi, a. D., Ueber die Entwickelung des sympathischen Nervensy stems.


Arch. mikr. Anat., Bd. XXVI, 1886.
Rabl, C, Ueber die IMetamerie des Wirbelthierkopfes. Verh. anat. Ges.,


A.o.fn.  
VI, 1892.
RuBASCHKiN, W., Ueber die Beziehungen des Nervus trigeminus zur Riech
schleimhaut. Anat. Anz., Bd. XXII, 1903.  
Weber, A., Contribution a Tetude de la metamerism du cerveau anterieur


chez quelques oiseaux. Arch, d'anat. microsc, Paris, T. Ill, 1900.
Van Wijhe, J. W., L^eber Somiten und Nerven im Kopfe von Vogel- und


Reptilien-embryonen. Zool. Anz. Bd. IX, 1886.


Ueber die Kopfsegmente und das Geruchsorgan der Wirbelthiere


Fig. 197. — Photograph of transverse section through a chick embryo of
Zool. Anz., Bd. IX, 1886.  
8 days.
A. o. m., Omphalomesenteric artery. Du., Duodenum. Giz., Gizzard.
Gon., Gonad. II., Ihum. M. D., Miillerian duct. Pc, Pancreas. V. umb.,  
Umbilical vein.  


It should also be noted that the absence of rotation of the
===Literature — Chapter IX===
chick's stomach (as contrasted with mammals) and the lesser
development of the great omentum appear to be the causes of
the more primitive position of the spleen in birds as contrasted
with mammals.


Organs of Special Sense


A. The Eye


==CHAPTER XII THE LATER DEVELOPMENT OF THE VASCULAR SYSTEM==
Addario, C, Sulla struttura del vitreo embryonale e de' neonati, sulla matrice del vitreo e suU' origine della zonula. Ann. OttalmoL, Anno 30,
1901-1902.




AddariOjC, Ueber die Matrix desGlaskorpers im menschlichen und thierischen


Auge. Vorlauf. Mitth. Anat. Anz., Bd. XXI, 19(32.
Agababow, Untersuchiingen iiber die Natur der Zonula ciliaris. Arch.


I. The Heart. (For an account of the earlier development,  
mikr. Anat., Bd. L, 1897.
Angelucci, a., Ueber Entwiekelung und Bau des vorderen Uvealtractus der


see Chapters V and VI.)
Vertebraten. Arch. mikr. Anat., Bd. XIX, 1881.
Arnold, J., Beitrage zur Entwickekmgsgeschichte des Auges. Heidelberg,


At the stage of seventy-two hours (Fig. 198), the ventricle
1874.
consists of a posterior transverse portion and two short parallel
AssHETON, R., On the Development of the Optic Nerve of Vertebrates, and  
limbs; the right limb is continuous with the bulbus arteriosus


from which it may be distinguished by
the Choroidal Fissure of Embryonic Life. Quar. Journ. Micr. Sc, Vol.  
a slight constriction, and the left limb
with the atrium. The constriction between the latter is the auricular canal.  
Between the two limbs in the interior
of the ventricle is a short bulbo-auricular septum separating the openings of
bulbus and atrium into the ventricle. A
slight groove, the interventricular sulcus,  
that extends backwards and to the right
from the bulbo-auricular angle, marks
the line of formation of the future interventricular septum (Fig. 199).  


The Development of the External
XXXIV, 1892.  
Form of the Heart. We have seen that
Bernd, Adolph Hugo, Die Entwiekelung des Pecten im Auge des Hiihn
in the process of development the heart
chens aus den Blattern der Augenblase. Bonn, 1905.  
shifts backwards into the thorax. The ventricle undergoes the
Cajal, S. R. y., Sur la morphologie et les connexions des elements de la retine
greatest displacement, owing to its relative freedom of movement, and thus comes to lie successively to the right of, and then
behind the atrium. A gradual rotation of the ventricular division
on its antero-posterior axis accompanies its posterior displacement;
and this takes place in such a way that the bulbus is transferred
to the mid-ventral line, where it lies between the auricles (Figs.  


199 and 200).  
des oiseaux. Anat. Anz. Bd. IV, 1889.  


The auricles arise as lateral expansions of the atrium, the
Sur la fine structure du lobe optique des oiseaux et sur I'origine reelle


348
des nerfs optiques. Int. Monatschr. Anat. u. Phys., Bd. VIII, 1891.
Cirincione, G., Ueber die Entwiekelung der Capsula perilenticularis. Arch.


Anat. u. Entw., Suppl. Bd., Jahrg. 1897.


Zur Entwiekelung des Wirbeltierauges. Ueber die Entwiekelung


Fig. 198. — Ventral view of
des Capsula perilenticularis. Leipzig, 1898.  
the heart of a chick embryo of 2.1 mm. head
length. (After Greil from
Hochstetter.)


Atr., Atrium. B. co.,
Ueber die Genese des Glaskorpers bei Wirbelthieren. Verh. Anat.  
Bulbus cordis, b. V., The
constriction between bulbus
and ventricle. C. au. v., Auriculo-ventricular canal. V.,
Ventricle.  


Ges., 17. Versamml. in Heidelberg, 1903.
Collin, R., Recherches sur le developpement du muscle sphincter de I'iris


chez les oiseaux. Bibliog. Anat., T. XII, fasc. V. Paris, 1903.
Froriep, a., Ueber die Entwiekelung des Sehnerven. Anat. Anz., Bd. VI,


LATER DEVELOPMENT OF VASCULAR SYSTEM
1891.


Die Entwiekelung des Auges der Wirbeltiere. Handb. der vergl. u.


exp. Entw.-l. der Wirbeltiere, Bd. II, 1905.
HuscHKE, E., Lieber die erste Entwiekelung des Auges und die damit zusam
menhangende Cyklopie. Meckel's Arch., 1832.
Kessler, L., Untersuchungen liber die Entwiekelung des Auges, angestellt


349
am Hiihnchen und Tauben. Dissertation. Dorpat, 1871.


Die Entwiekelung des Auges der Wirbelthiere. Leipzig, 1877.
V. Kolliker, a., LTeber die Entwiekelung und Bedeutung des Glaskorpers.


Verh. anat. Ges., 17. Vers. Heidelberg, 1903.


left one first at an early stage and the right one later. The left
Die Entwiekelung und Bedeutung des Glaskorpers. Zeitschr. wiss.  
auricle is thus larger than the right for a considerable period of
time in the early development. When the right auricle grows
out it passes above the bulbus, which is already in process of
rotation, and the two auricles then expand ventrally on each
side of the bulbus. The apex of the ventricle belongs primarily
to the left side and this remains obvious as long as the external
interventricular groove exists. In the adult the apex of the
heart belongs to the left ventricle.
 


Zool., Bd. LXXVII, 1904.
V. Lenhossek, M., Die Entwiekelung des Glaskorpers. Leipzig, 1903.
Lewis, W. H., Wandering Pigmented Cells Arising from the Epithelium of


the Optic Cup, with Observations on the Origin of the M. Sphincter


Fig. 199. — Ventral view of the heart of a
Pupillffi in the Chick. Am. Journ. Anat., Vol. II, 1903.
LocY, W. A., Contribution to the Structure and Development of the Vertebrate Head. Journ. Morph., Vol. XI. Boston, 1895.


chick embryo of 5 mm. head-length.  
Accessory Optic Vesicles in the Chick Embryo. Anat. Anz., Bd. XIV,


(After Masius.)
1897.
NussBAUM, M., Zur Riickbildung embryonaler Anlagen. (Corneal papillae


Atr. d., s., Right and left auricles.
of chick embryos.) Archiv. mikr. Anat., Bd. LVII, 1901.  
B. Co. Bulbus cordis. V. Ventricle.  






The varying positions occupied by the chambers of the heart in relation to the body axes constitute a serious difficulty in describing the
NussBAUM, M., Die Pars ciliaris retinae des Vogelauges. Arch. mikr. Anat., Bd.  
development. For instance, the auricular canal is at first in front of
the atrium (before any bending of the heart takes place). As the ventricular loop turns backward and beneath the atrium, the auricular
canal is ventral to the atrium ; and finally, as the ventricles assume their
definitive position behind the auricles, the derivatives of the auricular
canal (auriculo-ventricular openings) come to lie behind the atrium. In
other words, the atrium rotates around a transverse axis through nearly
180 degrees in such a way that its original anterior end becomes succes


LVII, 1901.


350
Die Entwiekelung der Binnenmuskeln des Aiiges der Wirbeltiere.


Arch. mikr. Anat., Bd. LVIII, 1901.
Rabl, C, Ziir Frage nach der Entwickehmg des Glaskorpers. Anat. Anz.,


Bd. XXII, 1903.


THE DEVELOPMENT OF THE CHICK
Ueber den Ban und die Entwickehmg der Linse. II. Reptihen imd


Vogel. Zeitschr. wiss. Zool., Bd. LXV, 1899.
Robinson, A., On the Formation and Structure of the Optic Nerve, and its


Relation to the Optic Stalk. Journ. Anat. and Phys. London, 1896.
SziLi, A.V. Beitrag zur Kenntniss der Anatomic und Entwickelungsgeschichte


sively ventral and posterior. The definitive ventral surface of the heart
der hinteren Irisschichten, etc. Arch. Opthalm., Bd. LIII, 1902.  
is a cranial rather than a ventral surface during the critical period of
development described below, up to eight days (cf. Figs. 148 and 150).  
In other words, the apex of the heart is directed ventrally rather than
posteriorly, though it has a posterior inclination. For simplicity of description, however, it seems better to use the definitive orientation in the
following account; that is, to regard the apex of the heart as posterior
instead of ventral, and the bulbus face of the heart as ventral instead
of cranial, in position.  


Zur Anatomic und Entwickelungsgeschichte der hinteren Irisschichten, etc. Anat. Anz., Bd. XX, 1901.


Zur Glaskorperfrage. Anat. Anz. Bd. XXIV, 1904.
ToRNATOLA, Origiuc et nature du corps vitre. Rev. gener. d 'opthalm. Annee


14, 1897.
UcKE, A., Epithelreste am Opticus und auf der Retina. Arch. mikr. Anat.,


Fig. 200. — Ventral view of the heart of a
Bd. XXXVIII, 1891.  
chick embryo of 7.5 mm. head-length. (After


Masius.)
Zur Entw^ickelung des Pigmentepithels der Retina. Diss, aus Dorpat.  


Atr. d., s., Right and left auricles. B. Co.,  
Petersburg, 1 89 1 .  
Bulbus cordis. V., Ventricle.
ViRCHOW, H., Facher, Zapfen, Leiste, Polster, Gefasse im Glaskorperraum


von Wirbelthieren, sowie damit in Verbindung stehenden Fragen. Er
gebn. Anat. u. Entw., Bd. X. Berlin, 1900.
Weysse, a. W., and Burgess, W. S., Histogenesis of the Retina. Am.


Naturalist, Vol. XL, 1906.


Division of the Cavities of the Heart. The embryonic
heart is primarily a single continuous tube; during development
a complex series of changes brings about its complete division
into right and left sides, corresponding to the pulmonary and
systemic circulations. Partitions or septa arise independently
in each primary division of the cardiac tube, excepting the sinus
venosus, and subsequently these unite in such a way as to make
two independent circulatory systems. During this time the




B. The Nose


LATER DEVELOPMENT OF VASCULAR SYSTE:\r 351
Born, G., Die Nasenhohlen und der Thranennasengang der amnioten Wir
belthiere II. Morph. Jahrb., Bd. V, 1879; Bd. VIII, 1883.
CoHN, Franz, Zur Entwickelungsgeschichte des Geruchsorgans des Hiihn
chens. Arch. mikr. Anat., Bd. LXI, 1903.
Dieulafe, Leon, Les fosses nasales des vertebres (morphologic et embry
ologie). Journ. de I'anat. et de la phys., T. 40 and 41, 1904 and 1905.


appropriate valves are formed. We have thus to describe the
(Translated by Hanau W. Loeb: Ann. of Otol., Rhin. and Laryng., Mar.,  
origin of three primary septa, viz., the interauricular septum,
the interventricular septum, and the septum of the truncus and  
bulbus arteriosus. These do not, however, themselves unite
directly, but are joined together by the intermediation of a fourth,
large, cushion-like septum formed in the auricular canal, i.e., in
the opening between the primitive atrium and ventricle.


In general it may be said that the development of the three
June and Sept., 1900.)
primary septa takes place from the periphery towards the center,  
Disse, J., Die erste Entwiekelung des Riechnerven. Anat. Hefte, Bd. IX,
i.e., towards the cushion-septum of the auricular canal, and that
it is practically synchronous in all three, though there is a slight
precedence of the interauricular septum. During the same time
the cushion-septum of the auricular canal is formed. We may
then consider first the origin of these septa separately, and second
their union.  


(o) The Septum Trunci et Bulbi Arteriosi (Septum AorticoPulmonale). This septum divides the truncus and bulbus arteriosus into two arteries, the aorta and pulmonary artery. Three
1897.  
divisions may be distinguished, viz., a part in the truncus arteriosus, a part in the distal division of the bulbus extending to
Ganin, M., Einige Thatsachen zur Frage iiber das Jacobsohn'sche Organ der
the place of formation of the semilunar valves, and a part in the
proximal portion of the bulbus, which subsequently becomes
incorporated in the ventricles. In mode of formation these are
more or less independent, though they unite to form a continuous
septum.


The septum of the truncus arteriosus arises on the fifth day
Vogel. Arb. d. naturf. Ges. Charkoff, 1890 (russisch). Abstr. Zool.  
as a complete partition extending from the cephalic border of
the two pulmonary arches into the upper portion of the bulbus
arteriosus; the blood current flowing through the bulbus that
passes behind this partition enters the pulmonary arches exclusively, that passing in front enters the two remaining pairs of aortic
arches. During the latter half of the fifth day and on the sixth
day the septum of the truncus is continued into the proximal portion of the bulbus and divides it in two stems. Here, however,
it co-operates with three longitudinal ridges of the endocardium
of the bulbus, one of which is in the direct line of prolongation of the septum of the truncus, which therefore is continued
along this one and between the other two as far as the place of
formation of the semilunar valves (Fig. 201). The entire septum
thus formed has a slightly spiral course, of such a nature that


Anz., 1890.
V. KoLLiKER, A., Ueber die Entwickehmg der Geruchsorgane beim Menschen


und Hiihnchen. Wiirzburger med. Zeitschr., Bd. I, 1860.
V. MiHALKOvics, v., Nasenhohle und Jacobson'sche Organ. Anat. Hefte,


352
I. Abth., Bd. XI, 1898.
Peter, Karl, Entwickehmg des Geruchsorgans und Jakobson'sche Organs


in der Reihe der Wirbeltiere. Bildung der ausseren Nase und des




THE DEVELOPMENT OF THE CHICK
Gaumens. Handbuch der vergl, und experiment. Entwickelimgslehre
 


der Wirbeltiere. IP, 1902.
Preobraschensky, L., Beitrage zur Lehre liber die Entwiekelung des Ge
ruchsorganes des Huhnes. Mitth. embryol. Inst. Wien, 1892.
PuTELLi, F., Ueber das Verhalten der Zellen der Riechschleimhaut bei


Hiihnerembryonen friiher Stadien. Mitth. embr. Inst. Wien, 1889.


C. The Ear


,  
Hasse, C, Beitrage zur Entwiekelung der Gewebe der hautigen Vogel
schnecke. Zeitschr. wiss. Zool., Bd. XVII, 1867.
HuscHKE, Ueber die erste Bildungsgeschichte des Auges und Ohres beim


bebriiteten Hiihnchen. Isis von Oken, 1831.
Kastschenko, N., Das Schlundspaltengebiet des Hiihnchens. Arch. Anat.


. AS. So p.  
u. Entw., 1887.
Keibel, Ueber die erste Bildung des Labyrinthanhanges. Anat. Anz., Bd.  


XVI, 1899.
Krause, R., Die Entwickekmg des Aquaeductus Vestibuh, s. Ductus endo
lymphaticus. Anat. Anz., Bd. XIX, 1901.


/
Die Entwickekmgsgeschichte des hautigen Bogenganges. Arch. mikr.


Anat., Bd. XXXV, 1890.
MoLDENHAUER, W., Die Entwickcking des mittleren und des ausseren Ohres.


/^
Morph. Jahrb., Bd. Ill, 1877.
PoLi, C, Sviluppo della vesicula auditiva; studio morphologico. Genoa,


1896.


(^S)
Zur Entwickekmg der Gehorblase bei den WirbeUieren. Arch. mikr.


Anat., Bd. XLVIII, 1897.
Retzius, G., Das Gehororgan der Wirbelthiere. II. Theil, Reptihen Vogel,


1
Sanger. Stockhokn. 1881-1884.
RoTHiG, p., und Brugsch, Theodor, Die Entwickekmg des Labyrintkes


beim Huhn. Archiv. mikr. Anat., Bd. LIX, 1902.
RtJDiNGER, Zur Entwickekmg des hautigen Bogenganges des inneren Ohres.


w
Sitzungsber. Akad. Miinchen, 1888.  
 
 
A.Sao.p.
 
 
 
Fig. 201. — A. Section through the
truneus arteriosus of an embryo of 5
mm. head-length.
B. Section through the distal portion of the bulbus arteriosus of the
same embryo. (After Greil.)
 
A., Aorta. P., PulmonaHs. A. S. ao
 
 
 
the pulmonalis, which lies dorsal to the aorta distally, is gradually
transposed to its left side. The third division of the aorticpulmonary septum arises near the opening of the bulbus into
the ventricle in the form of two ridges of the endocardium on
the right and left sides respectively of the bulbus, the pulmonary
 
division lying ventral and the
aortic division dorsal to the
incipient partition. A third
slight endocardial ridge of the
proximal part of the bulbus is
described (Hochstetter, Greil)
at this stage, but it soon disappears. The proximal bulbus
ridges may be seen on the fifth
day; on the sixth day they are
well formed; on the seventh day
they have united to form a partition w^hich becomes continup., Plane of the septum aortico-pulmo- qus with the partition in the
 
nale. 1, 2, and 3, Ridges prolonging DOrtion of the bulbus.
 
the septum aortico-pulmonale. ^tlStai poition oi ine u.uuus.
 
■ Thus the separation of the aortic and pulmonary trunk is completed down to the ventricle.
 
The semilunar valves arise by excavation of three endocardial thickenings in each trunk formed at the caudal end of the
distal division of the bulbus (Hochstetter, Greil). The origin
of these thickenings is as follows. Both the aortic and pulmonary
trunks receive one each of the original endocardial ridges of the
distal portion of the bulbus owing to the course of the aorticpulmonary septum. Each also receives half of the ridge along
which the septum of the truneus is prolonged. A third ridge
arises subsequently in each between these two. A cavity then
arises in each ridge and opens distally into the aorta and pulmonary artery respectively, thus forming pockets open in front.
These valves are fully formed at eight days.
 
The aortic-pulmonary septum becomes thick early in its
history and the muscular layers of the vascular trunks, which
at first form a common sheath for both, gradually constrict into
the septum, and separate when the constriction brings them
together, so that each vessel obtains an independent muscular
wall. Subsequently, a constriction extends from the outer layer
 
 
 
LATER DEVELOPMENT OF VASCULAR SYSTEM 353
 
of the truncus and bulbus along the entire length of the septum,
and thus completely separates the aorta and pulmonary arteries
from each other. On the eighth day each vessel has independent
muscular walls, and the external constriction has made some
progress.
 
(6) The Interventricular Septum. As noted before, the interventricular sulcus that extends from the bulbo-auricular angle
towards the apex of the heart marks the line of development of
the interventricular septum. The right division of the primitive
ventricle is therefore continuous with the bulbus and the left
with the atrium. However, the partition, bulbo-auricular septum, which at first separates the primitive right and left limbs
of the ventricle, undergoes rapid reduction and becomes a mere
ridge by the stage of ninety-six hours. Thus the opening of the
bulbus and the auricular canal lie side by side, separated only
by this slight ridge. The rotation of the ventricle brings the
bulbus from the right side into the mid-ventral line so that the
opening of the bulbus comes to lie ventral to the auricular canal
on its right side (cf. Figs. 199 and 200).
 
In the interior of the heart the development of the interventricular septum is associated with the formation of the trabeculse or ramified and anastomosing processes of the myocardium
that convert the peripheral part of the ventricular cavity into a
spongy mass at an early stage. Along the line of the interventricular sulcus these trabeculse extend farther into the cavity
than elsewhere, and become united together at their apices by a
slight thickening of the endocardium, which clothes them all,
thus originating the interventricular septum (Fig. 202). This
process begins at the apex of the ventricle, and extends towards
the base, the fleshy septum becoming gradually higher and thicker
and better organized. It thus has a concave free border, directed
towards the bulbo-auricular ridge and continued along both the
ventral and dorsal surfaces of the ventricle. The septum develops
more rapidly along the dorsal than the ventral wall and on the fifth
day reaches the neighborhood of the auricular canal on this side,
and unites with the right side of the fused endocardial cushions
which have in the meantime developed in the latter. (See below.)
Thus the interventricular foramen, or communication between
the ventricles, is gradually reduced in extent and limited to the
ventral anterior portion of the septum. It is never completely
 
 
 
354
 
 
 
THE DEVELOPMENT OF THE CHICK
 
 
 
closed, but, as we shall see later, the interventricular foramen
is iitilized in connecting up the aorta with the left ventricle.
 
It will be seen that if the original direction of this septum,
as indicated by the interventricular groove on the surface, were
preserved (Fig. 199), the interventricular septum would fuse
with the bulbo-auricular ridge and the right ventricle would then
be continuous with the bulbus only, and the left ventricle with
the atrium, and circulation of the blood would be impossible.
The avoidance of this condition is due to the rotation of the bulbus by which it is brought beneath the auricular canal, and by
widening of the auricular canal to the right. Thus the inter
 
 
 
FiG. 202. — Frontal section of the heart of a chick
embryo of 9 mm. head-length. (After Hochstetter.)
E. C, Median endothelial cushion. 1. E. C, Lateral endothelial cushion. S. Atr., Septum atriorum.
S. v., Septum ventriculorum.
 
 
 
ventricular septum meets the right side of the cushion-septum
and divides the auricular canal, though the opening of the bulbus
remains on its right.
 
(c) The inter auricular septum forms at the same time as the
septum between the ventricles, as a thin myocardial partition
arising from the vault of the atrium between the openings of the
sinus venosus and pulmonary vein; it extends rapidly with concave free border towards the auricular canal, and soon fuses
 
 
 
LATER DEVELOPMENT OF VASCULAR SYSTEM
 
 
 
355
 
 
 
completely along its entire free border with the endothelial
cushions of the latter. It would thus establish a complete partition between the two auricles were it not for the fact that
secondary perforations arise in it before its free edge meets the
endothelial cushions (Fig. 203). These have the same ph^^siological significance as the foramen ovale in the mammalian
heart, and persist through the
period of incubation, closing
soon after hatching.
 
(d) TheCushion-septum (Septum of the Auricular Canal).
This septum completes the entire system by uniting together
the three septa already considered. It forms as two cushionlike thickenings of the endothelium in the floor and roof respectively of the auricular canal
(cf. Figs. 202, 203 and 204).
These cushions rapidly thicken
so as to restrict the center of
the atrioventricular aperture,
and finally, fusing together, divide the latter into two vertically-elongated apertures, right
and left respectively. The time
of formation of this large endocardial cushion dividing the auricular canal is coincident with
the formation of the other septa.
 
(e) Completion of the Septa.
 
 
 
 
Fig. 203. — Reconstruction of the
 
heart of a chick embryo of 5.7 mm.
 
head-length, seen from right side.
 
Part of the wall of the right auricle
 
is cut away. (After Masius.)
 
B. Co., Bulbus cordis. D. C. Duct
of Cuvier. E. C. d., v., Dorsal and
ventral endothelial cushions. O.S.v.,
Opening of the sinus venosus into the
right auricle. 0. 1,0. 2, Primary and
secondary ostia or inter-auricular connections.
 
Thus bv the end of the fifth
 
 
 
or the beginning of the sixth day of incubation, the heart is
prepared for the rapid completion of a double circulation. The
embryonic circulation is never completely double, however, for
the reason that the embryonic respiratory organ (allantois)
belongs to the aortic system, and full pulmonary circulation does
not begin until after hatching. However, between the sixth
and eighth days the right and left chambers of the heart become
completely separated, except that the interauricular foramina
 
 
 
356
 
 
 
THE DEVELOPMENT OF THE CHICK
 
 
 
remain until hatching, and serve as a passageway of blood from
the right side to the left side.
 
The completion of the cardiac septa takes place in such a
way that the aorta becomes connected with the left ventricle,
the pulmonary artery remaining in connection with the right.
To understand how this occurs it is necessary to remember that,
although the bulbus arteriosus is primitively connected with the
right side of the ventricle, the revolution of the latter has transferred the bulbus to the middle line where it lies to the right of
 
 
 
 
Fig. 204. — Reconstruction of the heart of a
chick embryo of 5.7 mm. head-length. Ventral face removed; interior of the dorsal
half. (After Masius.)
Atr. d., s., Right and left auricles. D. C.
d., s., Right and left ducts of Cuvier. E. C,
Endothelial cushion, i. A. S., Interauricular septum. M. V., Opening of the meatus
venosus into the sinus. S. V., Sinus venosus.
V. d., s., Right and left ventricles.
 
the interventricular septum, and ventral to the right division of
the auricular canal. The bulbo-auricular ridge thus forms the
floor of this side of the auricular canal. The interventricular
septum is attached to the right side of the cushion-septum and
its foramen and the aperture of the bulbus lie side by side. It
will also be remembered that the proximal portion of the bulbus
is divided by a partition formed by right and left endocardial
 
 
 
LATER DEVELOPMENT OF VASCULAR SYSTEM 357
 
ridges, and that the aortic division of the bulbus hes above the
pulmonary division, that is, next the bulbo-aiiriciilar ridge.
The left bulbus ridge is thus continuous with the interventricular
septum immediately beneath the foramen of the latter, and the
right bulbus ridge lies on the opposite side.
 
The bulbus septum now becomes complete by fusion of the
right and left sides. The blood from the left ventricle is then
forced in each systole through the interventricular foramen and
along a groove in the right side of the cushion-septum into the
aortic trunk. This groove, how^ever, is open to the right ventricle also above the septum of the bulbus; but it is soon bridged
over by an extension of the cushion-septum along the bulboauricular ridge as far as the right side of the septum of the bulbus;
in this way the space existing between the interventricular septum and the opening of the aorta is converted into a tube, and
thus the aorta is prolonged through the cushion-septum, and
by way of the interventricular foramen into the left ventricle.
 
Fate of the Bulbus. The distal portion of the bulbus is converted into the proximal parts of the aorta and pulmonary artery.
The part proximal to the semilunar valves is gradually incorporated into the ventricles, owing to extension of the ventricular
cavities into its wall, and subsequent disappearance of the inner
wall of the undermined part.
 
The Sinus Venosus. (For earlier development see Chap. VI;
relation to septum trans versum. Chap. XI.)
 
In the course of development, the sinus venosus gradually
separates from the septum trans versum, though always connected
with the latter by the vena cava inferior. In early stages (up to
about 24 somites) it is placed quite symmetrically behind the
atrium, and extends transversely to the entrance of the ducts of
Cuvier on each side. The sinu-auricular aperture is approximately
in the median line at first, so that the right and left divisions of
the sinus are nearly symmetrical. The condition of approximate
bilateral symmetry of the sinus is, however, rapidly changed
by shifting of the sinu-auricalar aperture to the right side with
the outgrowth of the right auricle (24-36 somites); thus the left
horn of the sinus becomes elongated; moreover, the main expansion of the sinus takes place in the region of the sinu-auricular
aperture, and thus the left horn appears relatively narrow in diameter. The interauricular septum forms to the left of the sinu
 
 
358 THE DEVELOPMENT OF THE CHICK
 
auricular aperture (Fig. 204). At the stage of ninety-six hours the
o-eneral form of the sinus is that of a horseshoe situated between
the atrium and the septum trans versum; the ends of the horseshoe, or horns of the sinus venosus, are continued into the ducts
of Cuvier. The sinu-auricular aperture Ues on the right, and
here the cavity of the sinus is largest; the right horn of the sinus
is relatively short and the left horn forms a transverse piece on
the anterior face of the septum transversum, which gradually
curves dorsally and enters the left duct of Cuvier.
 
The right and left boundaries of the sinu-auricular aperture
project into the cavity of the right auricle as folds that meet
below the aperture and diverge dorsally (Fig. 204), thus forming
sinu-auricular valves; a special development of the muscular
trabecule running along the roof of the right auricle from the
angle of these valves corresponds to the septum spurium of mammalia. The sinus septum arises as a fold of the roof of the sinus
between the entrance of the left horn and the vena cava inferior;
it grows across the sinus into the sinu-auricular aperture and
thus divides the latter (cf. Fig. 231). Subsequently, the sinus
becomes incorporated in the right auricle, and the systemic
veins thus obtain independent openings into the latter (see account
of development of the venous system). The sinu-auricular
valves disappear during this process.
 
II. The Arterial System
 
The Aortic Arches. In the Amniota six aortic arches are
formed connecting the truncus arteriosus with the roots of the
dorsal aorta. The first four lie in the corresponding visceral
arches; the fifth and sixth are situated behind the fourth visceral
pouch; the fifth is a very small and transitory vessel, the existence of which was not suspected until comparatively recently
(v. Bemmelen, Boas), and the sixth or pulmonary arch was previously interpreted as the fifth. The discovery of the fifth arch
has brought the Amniota into agreement with the Amphibia
as regards the number and significance of the various aortic arches.
 
The fate of the aortic arches in the chick is as follows (see
Figs. 205, 206) : the first and second arches disappear as already
described (Chap. VI), and the anterior prolongation of the dorsal
aort2e in front of the third arch constitutes the internal carotid;
the ventral ends of the first and second arches form the external
 
 
 
LATER DEVELOPMENT OF VASCULAR SYSTEM
 
 
 
359
 
 
 
 
carotid. The third arch on each side persists as the proximal
portion of the internal carotids; and the dorsal aorta ruptures
on each side between the dorsal ends of the third and fourth
arches. The fourth arch and the root of the dorsal aorta disappear on the left side, but remain on the
right as the permanent arch of the aorta.
The fifth arch disappears on both sides;
the sixth arch persists throughout the
period of incubation and forms an important arterial channel of the systemic
circulation until hatching. Then the
dorsal portion (duct of Botallus or ductus arteriosus) becomes occluded, and
the remainder of the sixth arch becomes
the proximal portion of the pulmonary
arteries.
 
The details of these changes are as
follows: On the third and fourth days of
incubation the first and second aortic
arches disappear (Fig. 102). The lower
ends of these arches then appear as a
branch from the base of the third arch
on each side, extending into the mandible and forming the external carotid artery. The dorsal aorta in front of the
third arch constitutes the beginning of
the internal carotid. During the fourth
day the sixth pair of aortic arches is
formed behind the fourth cleft, and the
origin of the pulmonary arteries is transferred to them (Fig. 102). The fifth pair
of aortic arches is also formed during the fourth day (Fig. 206.)
It is a slender vessel passing from near the base to near the
summit of the sixth arch. As it has been entirely overlooked
by most investigators, it is certain that it is of very brief duration,
and it may even be entirely absent in some embryos. Apparently
it has no physiological importance, and it can be interpreted only
as a phylogenic rudiment.
 
Thus at the beginning of the fifth day the entire series of
aortic arches has been formed, and the first, second, and fifth
 
 
 
Fig. 205. — Diagram of
 
the aortic arches of birds
 
and their fate. (After
 
Boas.)
 
Car. com., Common carotid. Car. ext., External
carotid. Car. int., Internal
carotid. D. a., Ductus arteriosus. L., Left. p. A.,
Pulmonary artery. P.,
Right.
 
1, 2, 3, 4, 5, and 6, First,
second, third, fourth, fifth,
and sixth aortic arches.
 
 
 
360 THE DEVELOPMENT OF THE CHICK
 
have entirely disappeared. The surviving arches are the third
or carotid arch, the fourth or aortic arch, and the sixth or pulmonar}^ arch. Up to this time the development is symmetrical
 
on both sides of the body.
 
During the fifth and sixth
 
days the two sides become
 
asymmetrical, the fourth arch
 
becoming reduced on the left
 
side of the body and enlarged
 
on the right. Fig. 207 shows
 
the condition on the two sides
 
Fig. 206. — Camera sketch of the aortic of the body on the sixth day.
 
arches of the left side of a chick em- Jf the fourth arch of the two
 
bryo U days old. From an injected ^-^^^ ^^ compared it will be
 
specimen. (After Locy.) ,i . ,i ^ r.
 
Au 1 • +• • T?- one seen that the leit one is re
Abbreviations as m h ig. 205.
 
duced to a very narrow rudiment which has lost its connection with the bulbus arteriosus,
while on the right side it is well developed. Another important
change illustrated in the same figure is the reduction of the dorsal
aorta between the upper ends of the carotid and aortic arches to
a narrow connection. Two factors co-operate in the diminution
 
 
 
 
 
 
Fig. 207. — Reconstruction of the aortic arches of a 6-day
chick embryo from a series of sagittal sections.
 
A. Left side.
 
B. Right side.
 
Car. com., Common carotid. Car. ext., External carotid.
Car. int., Internal carotid. D. a., Ductus arteriosus.
3, 4, and 6, Third, fourth, and sixth aortic arches.
 
and gradual disappearance of this part of the primitive dorsal
aorta, viz., the elongation of the neck and the reduction of the
blood current. It will be seen that relatively little circulation
is possible in this section, because the current up the carotid
 
 
 
LATER DEVEL0P:\IEXT OF VASCULAR SYSTEM 361
 
arch turns forward and that up the aortic arch turns backward,
hence there is an intermediate region of stagnation, and here
the obUteration occurs.
 
On the eighth day the changes indicated on the sixth day
are completed. The left aortic arch has entirely disappeared,
and the connection between the upper ends of the carotid and
aortic arches is entirely lost on both sides (Fig. 208), though lines
of apparently degenerating cells can be seen between the two.
On the other hand, the upper end of the pulmonary arch (duct
of Botallus) is as strongly developed on both sides as the
right aortic arch itself. The pulmonary artery proper is relatively very minute (Fig. 208), and it can transmit only a small
 
 
 
<^M
 
 
 
 
 
A B.
 
Fig. 208. — Reconstruction of the aortic arches of an 8-day embryo from
a series of sagittal sections.
 
A. Left side.
 
B. Right side. . -si
A. o. m., Omphalomesenteric artery. Ao. A., Aortic (systemic) arch.
 
Car., Carotid. D. a., Ductus arteriosus, d. Ao., Dorsal aorta, p. A., Pulmonary artery. S'cl., Subclavian artery. V., Valves of the puhnonary
a,rtery.
 
quantity of blood; the principal function of the pulmonary arch
is obviously in connection with the systemic circulation. In
other words, both sides of the heart pump blood into the aorta
during embryonic life; after hatching, the duct of Botallus becomes occluded as already noted, and the pulmonary circulation
is then fully established.
 
The Carotid Arch. With the retreat of the heart into the
thorax, the internal and external carotids become drawn out into
long vessels extending through the neck region. The internal
carotids then become approximated beneath the vertebral centra.
The stem of the external carotid forms an anastomosis with the
internal carotid in the mandibular region, and then disappears,
 
 
 
362
 
 
 
THE DEVELOPMENT OF THE CHICK
 
 
 
Car. cow
 
 
 
s.cl.s
 
 
 
so that its branches appear secondarily as branches of the internal carotid. The common carotid (car. communis) of adult
anatomy is derived entirely from the proximal part of the internal carotid.
 
The Subclavian Artery. The primary subclavian artery
arises on the fourth day from the fifteenth (eighteenth of entire
 
series) segmental artery of
the body-wall when the
wing-bud forms, and gradually increases in importance with the growth of the
wdng. During the fifth day
a small artery that arises
from the base of the carotid
arch grows backwards and
unites with the primary subclavian at the root of the
wing. Thus the subclavian
artery obtains two roots, a
primary one from the dorsal
aorta and a secondary one
from the carotid arch (Fig.
209). As the latter grov/s
in importance the primary
root dwindles and finally
disappears (about the ninth
day). Apparently the Crocodilia and Chelonia agree
with the birds in this respect, while the other vertebrates retain the primary
root.
 
The Aortic System includes the aortic arch and
the primitive dorsal aorta
 
 
 
 
Fig. 209. — Dissection of the heart and
aortic arches of a chick embryo in the
latter part of the sixth day of incubation. (After Sabin.)
 
All., Auricle. Car. com., Common carotid. S'cl. d., s., primary and secondary
subclavian artery.
 
3, 4, 6, Third (carotid), fourth (systemic), and sixth (puhnonary) arches.
 
 
 
with its branches (Fig. 216).
 
The segmental arteries belong to the primitive dorsal aorta;
originally there is a pair in each intersomitic septum, but their
fate has not been thoroughly worked out in the chick. At six
days the cervical segmental arteries are united on each side by
 
 
 
LATER DEVELOPMENT OF VASCULAR SYSTEM 363
 
a longitudinal anastomosis communicating with the internal
carotid in front.
 
The two omphalomesenteric arteries are originally independent
(Chap. Y), but as the dorsal mesentery forms, they fuse in a
common stem extending to the umbilicus. The anterior mesenteric artery arises from this. The coeliac and posterior mesenteric arteries arise independently from the dorsal aorta (Fig. 216).
 
Mesonephric arteries arise from the ventro-lateral face of the
dorsal aorta and originally supply the glomeruli; they are very
numerous at ninety-six hours, but become much reduced in
number as the renal portal circulation develops; some of them
persist as the definitive renal and genital arteries.
 
The umbilical arteries arise from the same pair of segmental
arteries that furnishes the primitive artery of the leg. Thus
on the fourth day the umbilical arteries appear as branches of
the sciatic arteries; but later the umbilical arteries become much
larger than the sciatic (Fig. 216). The right umbilical artery is,
from the first, smaller than the left. On the eighth day its intermediate portion in the region of the neck of the allantois is much
constricted, and it gradually disappears. The caudal artery is
the narrow posterior extremity of the dorsal aorta behind the
umbilical arteries.
 
I do not find a stage in the chick when the umbilical arteries unite
directly with the dorsal aorta by way of the intestine and dorsal mesentery, though no doubt indirect connections exist at an early stage. In
mammals (Hochstetter) the primitive umbilical artery has such a
splanchnic course, but a secondary connection in the somatopleure soon
replaces the primary splanchnic path.
 
III. The Venous System. (See Chapter VI for origin of the
 
first venous trunks)
 
We shall take up the development of the venous system in
the following order: (a) the system of the anterior venae cavse
(venae cavse superiores) ; (5) the omphalomesenteric and umbilical veins and the hepatic portal system; (c) the system of the
inferior vena cava.
 
The anterior venae cavae are formed on each side b}' the
union of the jugular, vertebral, and subclavian veins. The jugular
is derived from the anterior cardinal veins, which extend down
the neck in close proximity to the vagus nerves. The embryonic
 
 
 
364 THE DEVELOPMENT OF THE CHICK
 
history of its branches is not known in detail (see Chap. VI and
Fig. 162 for the first branches). The history of the vertebral
veins, which open into the jugular veins near the base of the
neck, formed by union of anterior and posterior branches, is
likewise unknown. Presumably they are formed in part by
anastomoses between segmental veins. The subclavian vein
arises primitively as a branch of the posterior cardinal vein;
it receives the blood from the wing and walls of the thorax. The
part of the posterior cardinal behind the entrance of the subclavian vein disappears on the sixth day, and its most proximal
part represents then the anterior continuation of the subclavian
vein (Fig. 216). The part of the superior vena cava proximal
to the union of jugular and subclavian veins is derived from the
duct of Cuvier, and on the left side also from the left horn of
 
the sinus venosus.
 
The primitive omphalomesenteric veins unite behind the
sinus venosus to form the meatus venosus, around which the
substance of the liver develops as described in Chapters VI and
X; the union extends back to the space between the anterior
and posterior liver diverticula, where the omphalomesenteric
veins diverge and pass out to the yolk-sac along the margins
of the anterior intestinal portal (Fig. 210 A). In the latter part
of the third day (34-36 somites) an anastomosis forms between
the right and left omphalomesenteric veins above the intestine
just behind the dorsal pancreas, and thus establishes a venous
ring around the intestine, the upper portion of which is formee*.
by the anastomosis, the lower portion by the meatus venosus,
and the sides by the right and left omphalomesenteric veins
respectively (Fig. 210 B). Even during the formation of this
first venous ring it can be seen that its left side is becoming narrower than the right side, and in less than a day it disappears
completely (Fig. 210 C). Thus the blood brought in by the
left omphalomesenteric vein now passes through the dorsal
anastomosis to the right omphalomesenteric vein, and the latter
alone connects with the meatus venosus.
 
While this is taking place (seventy-two to ninety-six hours)
the intestine has elongated, the anterior intestinal portal has
shifted backwards, and a second anastomosis is formed between
the two omphalomesenteric veins ventral to the intestine and
immediately in front of the intestinal portal (Fig. 210 D). Thus
 
 
 
LATER DEVELOPMENT OF VASCULAR SYSTEM
 
 
 
365
 
 
 
a second venous ring is established around the ahmentary canal,
the lower portion of which is formed by the second anastomosis,
 
 
 
M^
 
 
 
//it.
 
 
 
' ■ \ Af.y.
 
 
 
 
 
 
A
 
 
 
Kr./ [ ^,
 
 
 
Ko/nX'
 
 
X ^'i/.s.
 
 
 
D.C. -- '
 
 
 
 
m.
 
 
 
n)
 
 
 
 
 
 
 
jy.
 
 
 
 
 
 
^ D
 
 
 
/r/-/
 
 
 
 
 
 
y.o..7?
 
 
 
 
 
 
 
/^:c.r.
 
 
 
Y.
 
 
 
Fig. 210. — Diagrams illustrating the development of the hepatic
portal circulation. (After Hochstetter.)
 
A. About the fifty-eighth hour.
 
B. About the sixty-fifth hour; first venous ring formed around
the intestine.
 
C. About the seventy-fifth hour; the left limb of the first venous ring has disappeared.
 
D. About the eightieth hour; the second venous ring is established.
 
E. About the one hundredth hour; the right limb of the second
venous ring has disappeared.
 
F. Hepatic circulation about the one hundred and thirtieth
hour, immediately before the disappearance of the intermediate
portion of the meatus venosus.
 
a. i. p., Anterior intestinal portal. D. C, Duct of Cuvier. int.,
Intestine. M. V., Meatus venosus. (Es., OEsophagus. Pc, Pancreas. St., Stomach. S. v.. Sinus venosus. V. c. i., Vena cava
inferior. V. h.. Hepatic veins. V. o. m.. Omphalomesenteric vein.
V. r. 1, First venous ring. v. r. 2, Second venous ring. V. u. d.,
Right umbilical vein. V. u. s., Left umbilical vein.
 
 
 
366 THE DEVELOPMENT OF THE CHICK
 
the upper portion by the first anastomosis, and the sides by the
right and left omphalomesenteric veins respectively. This ring
is^lso soon destroyed, this time by the narrowing and disappearance of its right side (Fig. 210 E).
 
Thus at about 100 hours the condition is as follows (Fig. 210
E) : the two omphalomesenteric veins unite to form a single trunk
in front of the anterior intestinal portal and ventral to the intestine (second anastomosis), the single trunk then turns to the left
(left side of second ring), passes forward and above the intestine
to the right side (first or dorsal anastomosis), and then farther
forward on the right side of the intestine (right side of first venous
ring) to enter the liver, where it becomes continuous with the
 
meatus venosus.
 
The Hepatic Portal Circulation becomes established in the
following manner: The meatus venosus is primarily a direct
passageway through the liver to the sinus venosus (Fig. 210 C);
but, as the liver trabecule increase, more and more of the blood
entering the meatus venosus is diverted into the vascular channels or sinusoids that occupy the spaces between the trabeculse.
By degrees these secondary channels through the liver substance
form two sets of vessels, an afferent one, branching out from
the caudal portion of the meatus venosus, in which the blood
is flowing into the hepatic sinusoids, and an efferent set branching from the cephalic portion of the meatus venosus in which
the blood is flowing from the hepatic sinusoids into the meatus
(210 D and E). By degrees the circulation through the liver
substance gains in importance, and liver trabeculse grow across
the intermediate portion of the meatus venosus (six to seven
days cf. Fig. 216), thus gradually occluding it as a direct path
through the liver (Fig. 210 F).
 
In this way there arises a set of afferent veins of the liver,
branches of the omphalomesenteric or hepatic portal vein, and
a set of efferent vessels which unite into right and left hepatic
veins opening into the cephalic portion of the original meatus
venosus. These veins begin to be differentiated after the one
hundredth hour of incubation, and the disappearance of the
intermediate portion of the meatus venosus as a direct route
through the liver is completed on the seventh day.
 
The original hepatic portal circulation is thus supplied mainly
with blood from the yolk-sac. But on the fifth day the mesen
 
 
LATER DEVELOPMEXT OF VASCULAR SYSTEM ' 367
 
teric vein begins to form as a small vessel situated in the dorsal
mesentery and opening into the omphalomesenteric vein behind
the dorsal pancreas. This vein increases in importance as the
development of the viscera proceeds, and becomes the definitive
hepatic portal vein; it receives branches from the stomach, intestine, pancreas, and spleen. The development of these branches
proceeds "pari passu with the development of the organs from
which they arise, and does not require detailed description. It
should be noted, however, that part of the veins from the gizzard and proventriculus form an independent vena porta sinistra
which enters the left lobe of the liver.
 
A distinct subintestinal vein extends forward from the root of the
tail at the stage of ninety-six hours to the posterior intestinal portal,
where it opens into the branch of the left omphalomesenteric vein,
that extends forward from the posterior end of the sinus terminalis.
This vein appears to take up blood from the allantois at an early stage.
However, it disappears at about the time when the umbilical vein becomes the functional vein of the allantois. Originally it appears to
open into s\Tnmetrical right and left branches of the omphalomesenteric vein that encircles the splanchnic umbilicus. The right branch
is, however, much reduced at ninety-six hours (cf. Hochstetter, 1888).
 
The Umbilical Veins. The umbilical veins appear as vessels
of the lateral body-wall opening into the ducts of Cuvier (Fig.
210 C; cf. Fig. 117); at first they show anastomoses with the
latter, which, however, soon disappear. They are subsequently
prolonged backwards in the somatopleure along the lateral closing
folds of the septum transversum (Chap. XI). Up to the end of
the third day of incubation they have no direct connection with
the blood-vessels of the allantois, and function only as veins of the
body-wall.
 
However, they obtain connection with the efferent vessels
of the allantois during the fourth day, apparently by widening
of parts of an intervening vascular network, and then the allantoic l)lood streams through them to the heart. The right umbilical vein disappears on the fourth day, and the left one alone
persists.
 
In the meantime the central ends of the umbilical veins have
acquired new connections. (Middle of third day. Fig. 210 D.)
This takes place through the formation of anastomoses, especially
on the left side, between the umbilical vein and the hepatic
 
 
 
368 THE DEVELOPMENT OF THE CHICK
 
vessels. (On the right side similar connections appear, according
to Brouha, but as the entire right umbilical vein soon degenerates
thev need not be considered farther.) The blood of the left umbilical vein thus divides and part flows into the duct of Cuvier by
way of the original termination, and part flows through the liver
into the meatus venosus. The original connection is then lost
and all of the blood of the umbilical vein flows through the liver
into the meatus venosus. Although the intrahepatic part is
at first composed of several channels, yet the blood of the umbilical vein flows fairly directly into the meatus venosus, and
thus takes no part in the hepatic portal circulation. On the
eighth day the entrance of the umbilical vein into the cephalic
part of the meatus venosus is still broken into several channels
by liver trabeculae (Fig. 182) ; these, however, soon disappear,
and the vein then empties directly into the meatus venosus, which
has in the meantime become the terminal part of the inferior
vena cava. As the ventral body-wall closes, the umbilical vein
comes to lie in the mid-ventral line, and in its course forward it
passes from the body-wall in between the right and left lobes
of the liver. The stem of the umbilical vein persists in the adult,
as a vein of the ventral body-wall opening into the left hepatic
vein.
 
The System of the Inferior Vena Cava (Post-cava). The
post-cava appears as a branch of the cephalic portion cf the meatus
venosus, and in its definitive condition the latter becomes its
cephalic segment; thus the hepatic and umbilical veins appear
secondarily as branches of the post-cava. The portion of the
post-cava behind the liver arises from parts of the postcardinal
and subcardinal veins, and receives all the blood of the posterior
portion of the body and viscera, that does not flow through the
hepatic portal system. The history of the development of this
vein, therefore, involves an account of (1) the origin of its proximal portion within the liver, and (2) of the transformation of the
postcardinals and subcardinals.
 
The proximal portion of the post-cava arises in part from
certain of the hepatic sinusoids in the dorsal part of the liver
on the right side at about the stage of ninety hours, and in part
from a series of venous islands found at the same time in the
caval fold of the plica mesogastrica (Figs. 211 and 212. See
Chap. XI). As the caval fold fuses Avith the right dorsal lobe of
 
 
 
LATER DEVELOPMENT OF VASCULAR SYSTEM
 
 
 
369
 
 
 
the liver, the venous islands flow together and establish a venous
trunk extending along and within the right dorsal lobe of the
liver, and opening anteriorly into the meatus venosus. At first
the connection with the meatus venosus lies near the sinus venosus, but in later stages is some cUstance behind the latter. Behind
the liver the dorsal attachment of the caval fold is to the ventral
surface of the right mesonephros, and at this place the vena cava
enters the mesonephros and connects with the subcardinal veins
(cf. Fig. 182).
 
The latter vessels arise as a series of venous islands on the
median surface of the mesonephros and lateral to the aorta on
each side. Such disconnected primordia are first evident at
 
 
 
l>.c.s.
V.u.s
 
 
 
^M--OCd.
 
 
 
V.u.d
 
 
 
 
U [[User:Z8600021|Mark Hill]] ([[User talk:Z8600021|talk]])'V.c.h
 
Fig. 21L — A drawing of a wax reconstruction of
 
the veins in the region of the liver of a sparrow
 
embryo. Outline of the liver represented by
 
broken lines. Dorsal view. (After Miller.)
 
D. C. d., s., Right and left ducts of Cuyier.
 
D. v., Ductus (meatus) venosus. S. V., Sinus
 
venosus. V.c. i., Vena cava inferior. V. u. d.,s.,
 
Right and left umbilical veins.
 
about the seventieth hour, and soon they run together to form
a longitudinal vessel on each side, which has temporary direct
connections with the postcardinals (Fig. 212), replaced afterwards (fifth day) by a renal portal circulation through the substance of the mesonephros. As the subcardinal veins enlarge,
they approach one another just behind the omphalomesenteric
artery beneath the aorta and fuse together (sixth day. Fig. 213).
In the meantime, the post-cava has become continuous with the
anterior end of the right subcardinal (Fig. 213).
 
The venous circulation is then as follows: The blood from
 
 
 
370
 
 
 
THE DEVELOPMENT OF THE CHICK
 
 
 
Ucp.d.
 
 
 
A-o.m.
 
 
 
 
Vsc.d.
 
 
 
LATER DEVELOPMENT OF VASCULAR SYSTEM 371
 
 
 
C. V.sc.d.
 
 
 
V3C.S.
 
 
 
V.c.i.
 
 
 
A.OM
 
 
 
V.c.fi.d.
 
 
 
Vscd.
 
 
 
 
Fig. 213. — Reconstruction of the venous system of
a chick of 5 days. Ventral view. (After Miller.)
a., Mesonephric veins. Ao., Aorta. A. sc. s., Left
sciatic vein. Other abbreviations as before.
 
the right and left postcardinal veins passes through the vascular network of the mesonephros, and empties into the subcardinal veins, from which it flows into the vena cava inferior,
and so through the meatus venosus to the heart. Prior to the
sixth day, however, the greater portion of the blood in tlie pos
 
 
FiG. 212. — Reconstruction of the venous system of a chick of 90 hours,
ventral view. (After Miller.)
A. o. m., Omphalomesenteric artery, a. sc. s.. Left sciatic artery. A.
u. s., Left umbilical artery, b., Vessels enclosed within ventral side of mesonephros. V. c. p. d., s., Ri^ht and left posterior cardinal veins. V. c. i.,
Vena cava inferior. V. sc. d., s., Right and left subcardinal veins.
 
 
 
372 THE DEVELOPMENT OF THE CHICK
 
terior cardinals passes forward to the ducts of Cuvier without
entering the mesonephric circulation. On the fifth and sixth
days the cephalic ends of the postcardinals gradually dwindle
and disappear (cf. Fig. 216); thus all of the blood entering the
postcardinals must pass through the mesonephros to the subcardinals, which thus become efferent vessels of the mesonephros;
and a complete renal-portal circulation is established.
 
This form of circulation continues during the period of functional activity of the mesonephroi, and as the latter gradually
atrophy, the portions of the subcardinals posterior to the anastomosis gradually disappear. A direct connection between the
post- and subcardinals is then established on each side, by way
of the great renal veins, which have in the meantime formed in
connection with the development of the kidney (Fig. 214).
 
The crural and ischiadic veins have, in the meantime, developed
in connection with the formation of the hind limbs, as branches
of the postcardinals. Thus the hinder portion of the latter becomes transformed into the common iliac veins, and at the hinder
end the postcardinals form an anastomosis (Fig. 214).
 
IV. The Embryonic Circulation
 
On the fourth day the blood is driven into the roots of the
dorsal aorta through three pairs of aortic arches, viz., the third
or carotid, the fourth or aortic, and the sixth or pulmonary. The
fifth pair of aortic arches is also functional for a time during this
day, but soon disappears. The blood passing ap the third or
carotid arch is directed forward through the internal and external
carotid arteries to the head; that passing up the fourth and
sixth arches turns backwards to enter the dorsal aorta, so that
there is an intermediate area of stagnation in the roots of the
dorsal aorta between the carotid and aortic arches; though this
is more or less problematical, the arrangement of the vessels renders such a condition very probable. A very small proportion of
the blood enters the rudimentary pulmonary arteries from the
sixth arch. The blood in the dorsal aorta passes backwards and
enters (1) the segmental arteries, (2) the omphalomesenteric
arteries, (3) the (rudimentary) umbilical arteries, and behind
the latter passes into the narrow continuation of the dorsal aortse,
still separate in this region, known as the caudal arteries.
 
The blood is returned to the heart through the sinus venosus
 
 
 
LATER DEVELOPMENT OF VASCULAR SYSTEM 373
 
 
 
 
Fig. 214. — Reconstruction of the venous system of a sparrow embryo,
corresponding to a chick of about 14 days. (After Miller.)
V. c.i. H., Intra-hepatic part of the vena cava inferior. V
Part of the vena cava inferior derived from the subcardinal vein.
Genital veins. V. i. e. d., s., Riorht and left vena iliaca externa
 
 
 
d., s.
 
 
 
c. i. SC,
 
V. V. g.,
 
V. i. i.,
 
Right and left vena intervertebralis lum
 
 
Vena iliaca interna. V. i. 1.
 
balls. V. r. m. d., s., Right and left great renal veins.
 
almost exclusively, the pulmonary veins being very rudimentary
at this stage. The veins entering the sinus venosus are the ducts
of Cuvier, and the meatus venosus. The former are made up
on each side by (1) the anterior cardinal vein, returning blood
from the head, (2) the posterior cardinal vein returning blood
from the veins of the Wolffian bodv, and the intersomitic veins,
(3) the umbilical veins returning blood mainly from the body
 
 
374
 
 
 
THE DEVELOPMENT OF THE CHICK
 
 
 
wall, inasmuch as direct connection with the veins of the allantois
is not yet established. The meatus venosus receives the omphalomesenteric veins, and the blood of the allantois by way of the
subintestinal vein (the latter arrangement of very brief duration).
Thus at this time all of the blood is mixed together in the
 
sinus venosus, viz., that re
 
 
A m^ CA.Q.rn.)
Ao.
I-!- Vsrs.
 
 
 
-- Vils.
 
 
 
 
ceived through the ducts of
Cuvier, presumal)ly venous,
and that received through
the meatus venosus, presumably arterial, owing to its
circulation in the superficial
vascular network of the yolksac. Apparently there is no
arrangement for separation
or discrimination in the redistribution of the blood.
But on the other hand it
should be noted that most
of the blood comes from the
yolk-sac, owing to the slight
 
 
 
Vu.d.
Fig. 215. — Region of the bifurcation of
the post-cava in the adult fowl. Ven
tral view (After Miller) development of the vessels
 
A.m. s. (A. o.m.), Omphalomesenteric , , , . .1 • x
artery. A. i. s., Left internal iliac artery, ot the embryo at this time;
V. c. i., Vena cava inferior. ^ V. i. c. d.,
Right common iliac vein. V. i. e. d., Right
external iliac vein. V. i. i. d., Right internal iliac vein. V. i. 1. s., Left vena mtervertebralis lumbalis. V. sr. s., Left
suprarenal vein. Vv. g., Genital veins.
Vv. r.m., Great renal veins.
 
 
 
and that the blood of the
embryo itself cannot be
highly venous owing to the
shortness of the circuit and
the delicate nature of the
embryonic tissues, which, no doubt, permit direct access of oxygen.
On the sixth day the embryonic circulation enters on a second
phase, owing to the changes in the structure of the heart and
arrangement of the vessels described in detail in the preceding
part of this chapter.
 
On the eighth day the circulation is as follows: The right
and left ventricles are completely separate, and the former
pumps the blood into the pulmonary trunk, the latter into the
aortic trunk. The carotid arteries arise from the base of the
aortic arch and convey the blood to the head, and also, by way
of the sul:»clavians, to the walls of the thorax and to the wing.
The left aortic arch has disappeared, and the right arch is con
 
 
LATER DE\ ELOPMEXT OF VASCULAR SYSTEM 375
 
tinuous with the dorsal aorta. The pulmonary trunk divides into
right and left arches from which the small pulmonary artery is
given off on each side, and the arch is continued without perceptible diminution in size as the ductus Botalli (ductus arteriosus) to the dorsal aorta. Thus the greater quantity of blood
pumped by botli sides of the heart passes into the dorsal aorta
by way of the right aortic arch, and the right and left ductus
Botalli; but part of the blood from the left ventricle passes into
the carotids. The main branches of the dorsal aorta are (1)
coeliac, distributed to stomach and liver mainh% (2) omphalomesenteric to the 3'Olk-sac and mesentery, (3) right and left
umbilical arteries (of which the left is much more important, the
right soon disappearing), to the allantois and leg, (4) segmental
arteries to the body-wall, (5) the caudal arteries.
 
The anterior venae cavae (former ducts of Cuvier) return the
blood from the head, wing, and walls of the thorax to the right
auricle; but owing to the formation of the sinus septum, the left
vena cava opens directly into the right auricle to the left of the
sinus valves, and the right one, also independently, to the right of
the sinus valves. The proximal portion of the vena cava
inferior is the original meatus venosus, and it receives the
right and left hepatic veins, the last of w^hich receives all the
blood from the allantois through the umbilical vein (original
left).
 
There is also an hepatic portal and a renal portal circulation.
The hepatic portal system is supplied with blood mainly from
the yolk-sac, but also from the veins of the alimentary canal by
the mesenteric vein; the latter is a relatively unimportant vessel
at eight da3^s, but groW'S in importance and becomes the entire
hepatic portal vein after absorption of the yolk-sac. The hepatic
portal vein branches wdthin the liver into a system of capillaries
which reunite to form the right and left hepatic veins. Thus
all the absorbed nutrient material passes through the capillaries
of the liver, where certain constituents are no doubt acted on
in some important, but little understood, way.
 
The renal portal circulation persists through the period of
functional activity of the mesonephros. The afferent vein is
the posterior cardinal which is supplied by the segmental veins
and the veins of the leg and tail. The blood flows through the
capillaries of the mesonephros into the subcardinal veins, and
 
 
 
376 THE DEVELOPMENT OF THE CHICK
 
hence to the vena cava inferior. With the degeneration of the
mesonephros, the subcardinals disappear in large part and the
postcardinals then empty directly into the vena cava inferior
by way of the renal veins, which have formed in the meantime.
The embryonic renal portal system of birds is similar in all essential respects to the permanent system of amphibia and constitutes a striking example of recapitulation. The left auricle of
the heart receives the small pulmonary veins.
 
Thus practically all of the blood is returned to the right auricle
of the heart; a considerable part of it is diverted into the left
auricle through the foramina in the septum atriorum, and thus
the blood reaches both ventricles. Complete systems of valves
prevent its regurgitation in any direction.
 
It is an interesting question to what extent the different kinds
of blood received by the right auricle remain separate and receive
special distribution through the body. The blood poured in by
the anterior venae cavse is purely venous, and it seems probable
from the arrangement of the sinus valves that it passes into the
ventricle of the same side, and so into the pulmonary arch and
through the ductus Botalli into the dorsal aorta, and thus in part
at least to the allantois where it is oxygenated. The blood coming
in through the posterior vena cava is purified and rich in nutrition,
for part of it comes from the allantois, where it has been oxygenated, and part has passed through the renal portal circulation,
where, no doubt, it has been purified of nitrogenous excretory
matter, and the remainder is mostly from the yolk-sac and hence
laden with nutrition. This blood appears to be diverted through
the foramen of the septum atriorum into the left auricle, and
thence to the left ventricle, and so out into the carotids and
aortic arch. It would seem, therefore, to be reasonably certain
that the carotids receive the purest and most nutritious blood,
for the blood in the dorsal aorta is mixed with the blood from
the right ventricle. There can be no reasonable doubt that the
heart is a more effective organ for separate and effective distribution of the various kinds of blood received by it than this account
would indicate. But further investigation is necessary to determine in what ways and to what extent this takes place.
 
At the time of hatching the following changes take place:
the umbilical arteries and vein are obliterated in the allantois,
owing to drying up of the latter; their stems remaining as relatively
 
 
 
 
Fig. 216. — Diagram of the relations of the main splanchnic blood vessels
 
on the sixth day of incubation.
 
A. c, CoeHac artery. Adv., Vena advehens. All., Allantois. A. m.. Mesenteric artery. Ao., Aorta. A. o. m., Omphalomesenteric artery. A. p.,
Pulmonary artery. A. sc. Sciatic artery. A. u. d.. Right umbilical artery.
A. u. s., Left umbilical artery. A. V., Vitelline arteries. Car. int., Internal
carotid. Car. ext.. External carotid. CI., Cloaca. D. a., Ductus arteriosus.
D. v., Ductus (meatus) venosus. Int., Intestine. J. e., External jugular
vein. J. i.. Internal jugular vein. Li., Liver. Scl., Subclavian artery. V.
c. a.. Anterior vena cava. V. c. i.. Inferior Vena cava. V. c. p.. Posterior
cardinal vein. V. m., Mesenteric vein. V. o. m., Omphalomesenteric vein.
Vp., Pulmonary vein. V. s'c, Subcardinal vein. V. s'cl., Subclavian vein.
V. u. (s.). Umbilical vein (left). V. V., Vitelline vein. W. B., Wolffian
body. Y. S., Yolk-sac. Y. St., Yolk-stalk.
 
 
 
LATER DEVELOPMENT OF VASCULAR SYSTEM 377
 
insignificant vessels. The veins of the yolk-sac likewise disappear. The ductus arteriosus (Botalli) is obliterated on both
sides, and becomes a solid cord uniting the pulmonary arteries
and arch of the aorta. Thus the blood from the right ventricle
is driven into the lungs, and the pulmonary artery enlarges.
The foramina in the septum atriorum gradually close, and so a
complete double circulation is established. The right auricle
receives all the systemic (venous blood), which is then driven
through the lungs by way of the pulmonary artery, and returned
in an oxygenated condition through the pulmonary veins to
the left auricle; thence to the left ventricle and out through the
aorta into the systemic circulation again.
 
 
 
CHAPTER XIII
 
THE URINOGENITAL SYSTEM
 
The history of the pronephros and the origin of the mesonephros have been ah'eady described (Chap. VI). We have now
to consider (1) the later history of the mesonephros, (2) the
development of the metanephros or permanent kidney, (3) the
development of the reproductive organs and their ducts, and
(4) the development of the suprarenals. All these organs form
an embryological unit, by virtue of their mode of origin and their
interrelations. Thus we find that the intermediate cell-mass is
significant for the development of all: its growth causes the formation of the Wolffian body, on the median face of which the gonads
arise. The secreting tubules and renal corpuscles of the permanent kidney are also derivatives of the intermediate cell-mass.
The Wolffian duct is derived from the same source, and by change
of function becomes the vas deferens, after functioning for a while
as the excretory duct of the mesonephros. Certain parts of the
mesonephros also enter into the construction of the testis. And
the Miillerian duct, which forms the oviduct of the female, is
derived from the epithelium covering the Wolffian body.
 
I. The Later History of the Mesonephros
In Chapter VI we traced the origin of the nephrogenous
tissue, and the differentiation of the first mesonephric tubules
within it. We saw that in each of the segments concerned a
number of balls of cells arises by condensation within the nephrogenous tissue, and that these become converted into vesicles.
We saw also that each vesicle sends out a tubular sprout from
its lateral side to the Wolffian duct, with which it unites; and
that its median face becomes converted into a renal corpuscle.
These processes take place sucessively in antero-posterior order
within the somites concerned, so that a series of stages in the
development of the tubules may be studied in the same embryo.
Moreover, all the tubules of a given somite do not develop simul
.378
 
 
 
THE URIXOGEXITAL SYSTEM
 
 
 
379
 
 
 
taneously: primary tubules are formed in each somite from the
most ventral portion of the nephrogenous tissue; then secondar}tubules later from an intermediate portion, and tertiary tubules
later yet from the dorsal portion.
 
Fig. 217 represents a transverse section through the middle
 
 
 
 
^»f^^5^° v'"'it>f ^i:^j#^^'
 
 
 
 
 
 
 
 
 
 
 
 
 
Fig. 217. — Transverse section through the middle of the
 
Wolffian body of a chick embryo of 96 hours.
 
Ao., Aorta. Coel., Coelome. Col. T., Collecting tubule.
Glom., Glomerulus, germ. Ep., Germinal epithelium. M's't.,
Mesentery, n. t., Nephrogenous tissue. T. 1,2, 3, Primary,
secondary, and tertiary mesonephric tubules. V. c. p., Posterior cardinal vein. W. D., Wolffian duct.
 
of the Wolffian body at the stage of ninety-six hours, showing a
primary, secondary, and tertiary tubule. The primary tubule
is typically differentiated; the secondary has formed the secreting
tubule and the rudiment of the renal corpuscle, but the tubule
does not yet open into the Wolffian duct, though it is connected
with it; the tertiary tubule is still in the vesicular stage. Some
undifferentiated nephrogenous tissue remains above the rudiment of the tertiary tubule, which makes it possible that quarternarv tubules mav be formed later.
 
Referring still to the same figure, it will be noted that the
Wolffian duct itself has formed a considerable evagination dorsomedially (collecting tubule), with which both secondary and
tertiary tubules are associated as well as the undifferentiated
nephrogenous tissue. Similar evaginations are formed along
the entire length of the functional portion of the mesonephros.
 
 
 
380
 
 
 
THE DEVELOPxAIEXT OF THE CHICK
 
 
 
0(,
 
 
 
ov
 
 
 
o
 
 
 
Q>(
 
 
 
o
 
 
 
OO,
 
 
 
o
 
 
 
o
 
 
 
o
 
 
 
o r
 
 
 
o
 
 
 
xoz
 
 
 
X22
 
 
-2ZIC
 
 
 
22YII
 
 
 
Fig. 114. A.
 
 
 
Figs. 218 and 219 illustrate the form of these evaginations in
duck embr3^os of 40 and 50 somites respectively, as they appear
in reconstructions of the posterior portion of the mesonephros.
 
It will be seen that they gradually
form sacs opening into the Wolffian
duct. Subsequently, by elongating,
these sacs form collecting tubules
that gather up the secretions of the
mesonephric tubules proper and conduct them to the Wolffian duct.
These conducting tubules are stated
to branch more or less; it is also
said that they are more highly developed in the duck than in the chick.
Felix proposes to call them mesonephric ureters.
 
In the case of the secondary and
tertiary tubules, three parts may be
distinguished : parts one and two (derived from the nephrogenous tissue)
I;. o\C ^rc the renal corpuscle and secreting
 
tubule respectively; the third part is
the collecting tubule derived by
evagination from the Wolffian duct.
In the case of the primary tubules,
a conducting part appears to be
formed secondarily, though in what
way is not clear.
 
The formation of new tubules
ceases on the fifth day, all the nephrogenous tissue being then used
up. Up to the eighth day at least
the tubules grow rapidly in length
and become more differentiated. The
result is a relatively enormous protrusion into the bodv-cavity on each
side of the dorsal mesentery. Degeneration of the tubules sets in
about the tenth or eleventh days,
and the tissue is gradually absorbed;
 
 
 
2Mir
 
 
 
 
 
 
'XSKT
 
 
 
THE URIXOGEXITAL SYSTEM
 
 
 
381
 
 
 
this process extends over the whole of the latter period of incubation, and is completed at hatching. Parts, however, remain
in the male in connection with the testis; non-functional remnants
 
 
 
O ^ °o o
O
 
O.'l
 
 
 
 
' ."fi.T •-.
 
 
 
yxxiii
 
 
 
n.T.
 
 
 
Fig. 219. — Profile reconstruction of part of the
 
mesonephros and diverticulum of the ureter of
 
a duck embryo of 50 somites. (After Schreiner.)
 
CI., Cloaca. Int., Intestine. Mn. T., Meso
nephric tubules, n. T., Nephrogenous tissue.
 
Ur Ureter W. D.. Wolffian duct.
 
XXXII, XXXIII, XXXIV, Somites of the
same number.
 
may also be detected in the female (p. 401). It is difficult to
state the exact period of beginning and cessation of function of
the mesonephric tubules. Judging from the histological appear
 
 
PiG 918 — Profile reconstruction of part of the Wolffian duct and primordia
of mesonephric tubules (represented by circles) of a duck embryo of 45
somites. (After Schreiner.)
YXTV XXV etc., position of the correspondmg somites. Lines 114 A,
 
114 B 114 C ^represent the positions of the sections shown in these figures.
 
 
 
382
 
 
 
THE DEVELOPMENT OF THE CHICK
 
 
 
ances, however, it is probable that secretion begins in the tubules
on the fifth day and increases in amount up to the eleventh day
at least, when signs of degeneration become numerous. Presumably the functional activity diminishes from this stage on, being
replaced by the secretion of the permanent kidney.
 
 
 
SrC:^
 
 
 
Gq/?.-%
 
 
 
 
 
 
 
Fig. 220. — Transverse section through the mesonephros
 
and neighboring parts of a 6-day chick, in the region of
 
the spleen.
 
Ao., Aorta, bl. V., Blood vessels (sinusoids). Caps., Capsule of renal corpuscle. Coel., Coelome. col. T., Collecting
tubule. D., Dorsal. Giz., Gizzard. Glom., Glomerulus.
Gon., Gonad. L., Left. Spl., Spleen. Sr. C, Cortical substance of the suprarenal, s. t., Secreting tubule. T. R.,
Tubal rid^e. V., Ventral. V. c. p., Posterior cardinal vein
V. s'c. 1., Left subcardinal vein. W. D., Wolffian duct.
 
Figs. 220 and 221 represent sections through the mesonephros
on the sixth and eighth days respectively (see also Fig. 222,
eleven days). The renal corpuscles show the typical capsule
and glomerulus, and relation to the secreting tubules. The latter
are considerably convoluted on the sixth day, much more so on
the eighth day. The conducting tubules can usually be distinguished by their smaller caliber and thinner walls. The Wolffian
 
 
 
THE URIXOGEXITAL SYSTEM
 
 
 
383
 
 
 
duct is situated near the dorso-lateral edge of the mesonephros,
and the opening of a collecting tubule into it is shown in Figure
220. The renal corpuscles are situated next the median face of
the Wolffian body. The space between the tubules is occupied
 
 
 
';7.f.o.z.
 
 
 
Mh'tr
 
 
 
 
-3.?V
iVJ).
 
 
 
apmm
 
 
 
 
Gon.l
 
 
 
Fig. 221. — Transverse section through the metanephros, mesonephros,
gonads and neighboring parts of an 8-day chick,
bl. v., Blood vessels (sinusoids). B. W., Body-wall. col. T. M't'n.,
Collecting tubules of the metanephros. M. D., Miillerian duct. M's't., Mesentery, n. t. i. z., Inner zone of nephrogenous tissue (metanephric). n. t. o.
z., Outer zone of the nephrogenous tissue. Symp. Gn., Sympathetic o^anghon of the twenty-first spinal ganglion. V. C, Centrum of vertebra. Other
abbreviations as before.
 
almost entirely by a wide vascular network of sinusoidal character; that is, the endothelial walls of the vessels are moulded
directly on the basement membrane of the tubules without any
intervening connective tissue. The circulation is described in the
chapter on the vascular system.
 
 
 
384 THE DEVELOPMENT OF THE CHICK
 
II. The Development of the Metaxephros or Permanent
 
Kidney
 
The metanephros or permanent kidney supplants the mesonephros in the course of development. It is derived from two
distinct embryonic primordial (1) the nephrogenous tissue of
the two or three posterior somites of the trunk (31 or 32 to 33),
which furnish the material out of which the renal corjxiscles
and secreting tubules develop; and (2) a diverticulum of the
posterior portion of the Wolffian duct (Fig. 219), which develops
by branching into the collecting tubules and definitive ureter.
The development of the kidney takes place in a mass of mesenchyme, known as the outer zone of the metanephrogenous tissue,
that furnishes the capsule and connective tissue elements of
the definitive kidney, in which also the vascular supply is developed
(Figs. 221 and 222). The cortical tubules of the kidney are
thus derived mainly from the nephrogenous tissue, and the medullary tubules and ureter from the metanephric diverticulum.
 
Thus the definitive kidney is analogous in mode of development to the mesonephros, and is best interpreted as its serial
homologue. This point of view may be regarded as definitely
established by the work of Schreiner, to which the reader is referred for a full account of the history of the subject.
 
The metanephric diverticulum, or primordium of the ureter
and collecting tubules, arises about the end of the fourth da}^ as
a rather broad diverticulum of the Wolffian duct at the convexity
of its terminal bend to the cloaca (Fig. 219). It grows out
dorsally, forming a little sac, which, however, soon begins to grow
forward median to the posterior cardinal vein and dorsal to the
mesonephros (Fig. 224); by the end of the fifth day its anterior
end has reached the level of the csecal appendages of the intestine, and on the eighth day its anterior end has reached its definitive position at the level of the vena cava inferior, near to the
anterior end of the mesonephros (twenty-first definitive somite or
twenty-fifth of the entire series; cf. Fig. 150).
 
It should be noted that the metanephric diverticulum is similar
in its mode of origin to the so-called mesonephric ureters. It
may in fact be regarded as the posterior member of this series,
but it is separated from those that form the collecting tubules of
the mesonephros by at least two somites in which no diverticula
 
 
 
THE URINOGEXITAL SYSTEM
 
 
 
385
 
 
 
of the mesonephros are formed (Fig. 219). During its growth
forward a series of small diverticula arise from its wall and extend
dorsally (Fig. 223); these branch secondarily in a generally dichot
 
 
,'-''^i,< ■•'>"!■'■-■<- ■■■■---■: .
 
 
 
 
 
 
Af^Y.
 
 
 
^y^
 
 
 
 
Fig. 222. -Transverse section through the metanephros, mesonephros
gonads and neighboring structures of an 11-day male chick,
a. A. S., Abdominal air-.sac. Ao., Aorta B W Rndv wall r^^i n
 
duct. Mst., .Mesentery. M't'n., Metanephros. Sp., Spine of neural areh
 
W D^'woMandScrotr' '\t """.'^' "*'. J e.^., Vna ca"™ Meri*:
vv . u., \^ oiman duct. Other abbreviations as before.
 
 
 
386
 
 
 
THE DEVELOPMENT OF THE CHICK
 
 
 
 
Fig. 223. — Profile reconstruction of the Wolffian
duct and primordium of the metanephros of a
chick embryo of 6 days and 8 hours. (After
Schreiner.)
 
XXV to XXXIH, twentv-fifth to thirty-third
somites. Al. N., Neck of allantois. CI., Cloaca.
Int., Intestine. M's'n., Mesonephros. n. T.,
Nephroojenous tissue of the metanephros included
within the dotted lines. W. D., Wolffian duct.
Ur., Ureter.
 
 
 
THE URIXOGEXITAL SYSTEM 387
 
omoiis manner, and it is from them that the collecting tubules
of the kidney arise; the posterior unbranched portion of the metanephric diverticulum represents the definitive ureter.
 
The following data concerning these branches should be noted:
 
(1) the first ones are formed from the posterior portion of the
metanephric diverticulum, and the process progresses in an
anterior direction. This is the reverse direction of the usual order
of embryonic differentiation, but the reason for the order is the
same, viz., that differentiation begins in the first formed parts.
 
(2) A posterior, smaller group of collecting tubules is separated
at first by an unbranched portion of the ureter from an anterior
larger group (Fig. 223). The unbranched region corresponds to
the position of the umbilical arteries which cross here. (3) During
the fifth and sixth days the terminal portion of the Wolffian
duct common to both mesonephros and metanephros is gradually
drawn into the cloaca, and thus the ureter obtains an opening
into the cloaca independent of the Wolffian duct and posterior
to it (Fig. 223).
 
The Nephrogenous Tissue of the Metanephros. The nephrogenous tissue of the thirty-first, thirty-second, and thirty-third
somites is at first continuous with the mesonephros (Figs. 218
and 219), but on the fourth and fifth da3^s that portion situated
immediately behind the mesonephros degenerates, thus leading
to a complete separation of the most posterior portion situated
in the neighborhood of the metanephric diverticulum. This constitutes the metanephrogenous tissue proper (inner zone). It is
important to understand thoroughly its relations to the metanephric diverticulum. This is indicated in Fig. 219, which represents a graphic reconstruction of these parts in a duck embryo
of 50 somites. It will be seen that the metanephrogenous tissue
covers nearly the entire metanephric diverticulum; a transverse
section (Fig. 224) shows that it lies on its median side. The
outer dotted line (Fig. 219) gives the contour of a dense portion
of mesenchyme related to the diverticulum and nephrogenous
tissue proper. In section this forms a rather ill-defined area
shading into the nephrogenous tissue on the one hand and into
the surrounding mesenchyme on the other.
 
Fig. 224 shows the relations of the three constituent elements
of the kidney at the end of the fifth day, as seen in a transverse
section. The metanephric diverticulum lies on the median side
 
 
 
388
 
 
 
THE DEVELOPMENT OF THE CHICK
 
 
 
of the cardinal vein, and is in contact, on its median face, with
the proper nephrogenous tissue (inner zone); the latter shades
into the outer zone, the cells of which are arranged concentrically
with reference to the other parts. The relations subsequently
established may be summarized in a few Avords; the inner zone
of tissue grows and branches pari passu with the growth and
branching of the metanephric diverticulum, so that the termination of every collecting tubule is accompanied by a portion of
 
 
 
 
Fig. 224. — Transverse section through the
 
ureter and metanephrogenous tissue of a
 
5-day chick.
 
A. umb., Umbilical artery. Coel., Coelome.
 
M's't., Mesentery, n. t. i. z., Inner zone of the
 
nephrogenous tissue, n. t. o. z., Outer zone of
 
the nephrogenous tissue. Ur., Ureter. V. c.p.,
 
Posterior cardinal vein. W. D., Wolffian duct.
 
the inner zone, which is, however, always distinct from it. This
conclusion is established by the fact that from the start the two
elements, collecting tubules and inner zone, are distinct and
may be traced continuously through every stage. The outer
zone differentiates in advance of the two more essential constituents at all stages, and thus forms a rather thick investment
 
for them.
 
The formation of the secreting tubules from the inner zone
 
 
 
THE URIXOGEXITAL SYSTEM
 
 
 
389
 
 
 
 
Fig. 225. — Sections of the embryonic metanephros of the chick
to show developing tubules. (After Schreiner.)
 
A. Nephric vesicle or primordium of secreting tubule (ur. t )
and collecting tubule (col. T.); 9 days and 4 hours.
 
B. Elongation of nephric vesicle; same embryo.
 
C. Indication of renal corpuscle at the distal end of the
forming tubule.
 
D. The secreting tubule appears S-shaped.
 
E. Secreting tubule well formed; 9 davs and 21 hours.
 
F. Secreting tubule opening into collecting tubule; 11 days.
 
 
 
390 THE DEVELOPMENT OF THE CHICK
 
of the metanephrogenous tissue takes place in essentially the
same manner as the formation of the mesonephric tubules. The
first stages may be found in seven and eight-day chicks in the
portion of the kidney behind the umbilical arteries. The inner
zone tissue begins to arrange itself in the form of minute balls
of cells in immediate contact with the secreting tubules; a small
lumen then arises within the ball, transforming it into a thickwalled epithelial vesicle with radially arranged cells. The vesicle
then elongates away from the collecting tubule and gradually
takes on an S-shape. The distal end of the S becomes converted into a renal corpuscle as illustrated in Figure 225
and the proximal end fuses with the wall of the collecting tubule;
an opening is then formed between the two.
 
On the eleventh day of incubation, secreting tubules are thus
formed throughout the entire length of the kidney; but the histological structure does not yet give the effect of an actively secreting gland, although degeneration of the mesonephros has already
begun. The full development of the nephric tubules in the
chick has not been studied.
 
At all stages in its develojDment the kidney substance is
separated from the mesonephros by a distinct layer of undifferentiated mesenchyme, which is, however, at certain times extremely thin. But there is no evidence that at any time elements
of the mesonephros, e.g., undifferentiated nephrogenous tissue,
extend up into the metanephric primordium which so closely
overlies it (cf. Figs. 221 and 222).
 
The kidney is entirely retroperitoneal in its formation, and
its primary capsule is established by differentiation of the periphery of the outer zone. This may be seen in process at eleven
days (Fig. 222) : the primary capsule is definitely estal^lished on
its median and lateral sides; but is defective dorsally and at the
angle next the aorta. With the subsequent degeneration of the
mesonephros, and projection of the kidney into the coelome,
its ventral surface acquires a secondary peritoneal capsule.
 
III. The Organs of Reproduction
 
The gonads are laid down on the median surface, and the
ducts on the lateral surface of the Wolffian body, which thus
becomes converted into a urinogenital ridge. The composition
of the urinogenital ridge is at first the same in all embryos, whether
 
 
 
THE URIXOGENITAL SYSTEM 391
 
destined to become male or female. It has three divisions:
(1) the anterior or sexual division, containing the gonad, involves
about the anterior half of the Wolffian body; (2) a non-sexual
region of the Wolffian body occurs behind the gonad, and
(3) behind the Wolffian body itself the urinogenital ridge contains only the Wolffian and Mullerian ducts. A transverse section through the anterior division shows the following relations
(Fig. 221): on the mecUan surface the gonad, on the lateral surface near the dorsal angle of the body-cavity the Wolffian and
Mullerian ducts, the latter external and dorsal to the former:
between the gonad and ducts lie the tubules of the Wolffian
body destined to degenerate for the most part.
 
There is an incUfferent stage of the reproductive system
during which the sex of the embryo cannot be determined, either
bv the structure of the gonad or the degree or mode of development of the ducts. In those embryos that become males the
gonad develops into a testis, the Wolffian duct becomes the vas
deferens, the tubules of the anterior part of the Wolffian body
become the epididymis, those of the non-sexual part degenerate,
leaving a rudiment known as the paradidymis, and the Mullerian
duct becomes rudimentary or disappears. In embryos that become females, the gonad develops into an ovary; the Wolffian duct
disappears or becomes rudimentary, the Mullerian duct develops
into the oviduct on the left side and disappears on the right side,
and the tubules of the Wolffian body degenerate, excepting that
functionless homologues of the epididymis and paradidymis persist, known as the epoophoron and paroophoron respectively.
 
It is not correct to state, as is sometimes done, that the
embryo is primitively hermaphrodite, for, though the ducts characteristic of both sexes develop equally in all embryos, the primitive gonad is, typically, only indifferent. Nevertheless, if the
gonad be physiologically as well as morphologically indifferent
in its primitive condition, the possibility of an hermaphrodite
development is given. The primitive embryonic conditions
appear to furnish a basis for any degree of development of the
organs of both sexes.
 
Development of Ovary and Testis. Indifferent Period. The
reproductive cells of ovary and testis alike arise from a strip
of peritoneal epithelium, known as the germinal epithelium,
which is differentiated on the fourth day by its greater thickness
 
 
 
392 THE DEVELOPMENT OF THE CHICK
 
from the adjacent peritoneum (Fig. 217). The germinal epithelium lies between the base of the mesentery and the mesonephros
at first, but as the latter grows and projects into the body-cavity
the germinal epithelium is drawn on to its median surface. It is
difficult to determine its antero-posterior extent in early stages;
it begins near the point of origin of the omphalomesenteric arteries,
and its posterior termination is indefinite, but it certainly extends
over seven or eight somites.
 
Two kinds of cells are found in the germinal epithelium, viz.,
the ordinary peritoneal cells and the primordial germ-cells. The
latter are typically round, and several times as large as the
peritoneal cells (Figs. 226 and 227); the cytoplasm is clear
but contains persistent yolk granules and a large attraction
sphere, and the nucleus contains one or two nucleoli; they
are sharply distinguishable from the peritoneal cells, and they
may be traced through a continuous series of later developmental stages into the ova and spermatozoa. The origin of
these primordial germ-cells is therefore a matter of considerable
interest.
 
Two views have been held: (1) that they are derived from
the peritoneal cells, and (2) that they have an independent history
antecedent to the differentiation of a germinal epithelium, representing in fact undifferentiated embryonic cells that reach the
germinal epithelium by migration from their original source.
The former view was due to Waldeyer, and was supported by
observations of cells intermediate in structure between the primordial germ-cells and cells of the peritoneum (e.g. by Semon).
These observations have, however, been shown to be erroneous.
The second view has been demonstrated for a considerable number
of vertebrates; and quite recently Swift has shown that the
primordial germ-cells of the chick arise from the germ-wall at the
anterior margin of the pellucid area in a late stage of the primitive
streak; that they later enter the blood stream and are carried
into the embryo; some, which reach various inappropriate positions, degenerate; but others leaving the blood near the base of
the mesentery reach the germinal epithelium by migration. The
independent and early origin of germ-cells has an obvious
bearing on the theory of the continuity of the germ-plasm of
Weismann.
 
 
 
THE URINOGENITAL SYSTEM
 
 
 
393
 
 
 
Two other epithelial constituents enter into the composition of
the indifferent gonad, viz.: the rete tissue or cords of the urinogenital union, and the sexual cords. These lie between the germinal epithelium and the glomeruli of the Wolffian body. Between
these elements is a sparse mesenchyme continuous with the surrounding mesenchyme, constituting the stroma of the gonad.
 
 
 
.*,^
 
 
 
V
 
 
 
ty.b
 
 
 
 
 
 
 
 
 
• V^
 
 
 
^V^.-_
 
 
 
 
 
 
 
;*
 
 
 
m
 
 
 
w -*■•« ' * '
 
 
 
'A~s t.
 
 
 
Fig. 226. — Cross-section through the genital primordium of Limosa segocephala. (After Hoffmann, from Fehx and Biihler.)
 
The stage is similar to that of a chick embryo of 4| days.
 
Germ., Germinal epithelium. Mst., Mesentery. S. C., Rete cords.
v., Posterior cardinal vein. W. D., Wolffian duct.
 
 
 
Some primordial germ-cells occur in the stroma, though most are
in the germinal epithelium.
 
The rete cords appear within the gonad on the fifth day;
they are solid cords of epithelial cells that fill up the interior
 
 
 
394 THE DEVELOPMENT OF THE CHICK
 
of the gonad and cause it to protrude from the surface of the
Wolffian body (Fig. 226); the cords extend from the germinal
epithelium towards the hilum of the gonad (represented at this
time by the broad surface opposed to the Wolffian body), and
into the Wolffian body where they enter into close connection
with the renal corpuscles. In the Wolffian body and intermediate
zone they are very irregular in their course and connected by
numerous anastomoses, corresponding to the rete region of the
future testis. Strands of these cells pass dorsally, and, according
to some authors, form the cortical cords of the suprarenal capsules
(Fig. 226).
 
The following views of the origin of the rete cords in birds
have been held: (1) That they arise as outgrowths of the capsules
of renal corpuscles (Hoffmann, Semon) and the neck of the
Wolffian tubules also (Semon); (2) that they are ingrowths of
the germinal epithelium (Janosik); (3) that they differentiate
from the stroma (Prenant, Firket). The subject is a somewhat
difficult and complicated one, but the view that the rete cords
arise as outgrowths of the capsules of renal corpuscles brings the
birds into line, in this respect, with the reptiles and amphibia.
Hoffmann's observation that the rete cords lie at first on the
lateral side of the blood-vessels intervening between the germinal
epithelium and the Wolffian body, and that the cells of the cords
are directly continuous with those of the capsules, should be
conclusive.
 
The sexual cords arise as proliferations of the germinal epithelium which appear as buds projecting into the stroma (Fig.
227). They are definitely limited in time of origin between the
middle of the fifth and sixth days of incubation (Swift). They
carry with them numerous primordial germ-cells from the germinal
epithelium. About the end of the sixth day all free themselves
from the germinal epithelium, and a layer of stroma begins to
separate them sharply from the latter. They are destined to
form the seminiferous tubules in the male, and the so-called
medullary cords in the female.
 
Sexual Differentiation. The period of morphological indifference of the gonad is relatively long and the actual sexual differentiation appears slowly. It manifests itself (1) in differences in
the behavior of the germinal epithelium; (2) of the sexual cords;
 
 
 
THE URINOGENITAL SYSTEM
 
 
 
395
 
 
 
(3) larger size of the left ovary and ultimate disappearance of the
right one; (4) behavior of the stroma, particularly the albuginea.
The sex of the embryo can first be definitely determined about
the 156th hour, by the relative sizes of the two gonads, by the behavior of the germinal epithelium and by the presence of a larger
 
 
 
K,'-^
 
 
 
 
 
 
germ. ep.
 
 
 
pro.
 
 
 
m.
 
 
 
y^''^/.
 
 
 
 
 
 
4
 
 
 
 
 
coelom
 
 
 
 
 
.fSf
 
 
 
 
 
 
 
 
 
 
 
 
Fig. 227. — Portion of a transverse section through an
ovary of a 6^ day chick embryo (after Swift), germ,
ep., germinal epitheHum. m. c, sexual cord. pr. o.,
primordial germ-cells.
 
number of primordial germ-cells in the germinal epithelium of
 
the female. (Swift.)
 
As already stated, the sexual cords form the seminiferous
tubules of the testis; they are made up of two kinds of cells, viz.:
the primordial germ-cells and the ordinary peritoneal cells derived
from the germinal epithelium. After the seventh day they constitute most of the bulk of the testis, and the rete cords are pressed
towards the hilum by the sexual cords which radiate in that direc
 
 
396
 
 
 
THE DEVELOPIMENT OF THE CHICK
 
 
 
tion. The sexual cords now begin to branch and anastomose,
and soon form a reticulmn with mesenchyme in the meshes. About
the thirteenth day the primordial germ-cells, which have been
inactive, begin to divide, and a rapid increase in numbers ensues.
 
 
 
Intc. sir.
 
 
 
 
> -*=
 
 
 
 
 
 
m^f
 
 
 
 
 
 
'^:y/:
 
 
 
•%
 
 
 
vSJ*;*
 
 
 
?^:
 
 
 
.?*'
 
 
 
?,i'
 
 
 
 
 
 
Fig. 228. — Portion of a transverse section through the right testis of a
20 day chick embryo. The section shows a seminiferous cord in which a
lumen is beginning to develop. Note the position and polarization of the
spermatogonia (after Swift).
Int. c, interstitial cells. L., beginning of lumen. M. C, Mitochondrial
granules within a spermatogonium, p. c, supporting cells, derivatives of
peritoneal cells of the sexual cords, s. c, seminiferous cord, sp., spermatogonia, str., stroma.
 
The sexual cords are solid up to about the twentieth day of incubation; a lumen then begins to appear and they become transformed into tubules (Fig. 228). The primordial germ-cells form
the spermatogonia, and the peritoneal cells form the supporting
cells of the seminiferous tubules (Swift).
 
After the sixth day the germinal epithelium of the testis
rapidly retrogresses and becomes reduced to a thin peritoneal
 
 
 
THE URIXOGENITAL SYSTEM 397
 
endothelium. The stroma of the primitive testis remains scanty
up to the eleventh day. It then increases rapidly between the
sexual cords and also forms a layer between germinal epithelium
and seminiferous tubules, which becomes the albuginea. Interstitial cells appear in the stroma of the testis about the thirteenth
day and increase so rapidly as to form an immense amount by the
twentieth day (Swift).
 
As the testis increases in size it projects more from the surface of the Wolffian body, and folds arise above and below it
as well as in front and behind, that progressively narrow the
surface of apposition, which in this way becomes gradually
reduced to form the hilum of the testis, through which the rete
cords pass to the neighboring renal corpuscles (cf. Figs. 221 and
 
222).
 
As the testis is attached to the anterior portion of the Wolffian
body, the latter may be divided in two portions, an anterior
sexual and a posterior non-sexual portion. In the latter part of
the period of incubation the non-sexual portion undergoes absorption while the anterior portion becomes converted into the
 
epididymis.
 
The irregularly anastomosing rete cords in the region of the
hilum are united to the neighboring renal corpuscles by the original
strands and these form the vasa efferentia. In order to complete
the urinogenital union it is necessary that the rete cords unite
with the seminiferous tubules. The exact manner in which this
takes place has not been worked out for the chick; but there is
no doubt that this union does take place so that the seminiferous
tubules connect by way of the rete with the mesonephric tubules
and thus with the Wolffian duct.
 
As regards the formation of the epididymis: the renal corpuscles
of the Wolffian tubules concerned diminish in size, the glomerulus disappears and the cells of the capsule become cylindrical.
These changes progress from the lateral side of the Wolffian
body towards the testis; that is to say, the more lateral corpuscles
are first affected. A rudiment of the non-sexual part of the
Wolffian body persists in the . mesorchium of the male, between
testis and kidney. It is known as the paradidymis.
 
The development of the ovary in the chick has been studied
in recent years by Firket and by Swift.
 
The right ovary never undergoes much development after
 
 
 
398
 
 
 
THE DEVELOPMENT OF THE CHICK
 
 
 
the indifferent stage; it is destined to retrogress, and finally it
disappears.
 
In the indifferent gonad the sexual cords are formed in the
same way whether the organ is to become ovary or testis; but,
whereas in the case of the testis these cords are destined to form
the functional seminiferous tubules, in the case of the ovary they
form only the cords of the medulla. The cortex of the ovary
which includes the functional follicles develops from a second
 
 
 
 
Fig. 229. — Cross-section of the ovary of a young embryo of Numenius
arcuatus. (After Hoffmann.)
bl. v., Blood-vessel, germ. Ep., Germinal epithelium, r., rete ovarii.
s. c, Sexual cord.
 
proHferation of the germinal epithelium. The sexual cords cease
to grow, and become converted into tubes with a wide lumen,
and low epithehum; shortly after hatching they entirely disappear.
 
The characteristic feature of the development of the ovary is
a second period of intensive growth of the germinal epithelium
accompanied by a rapid increase of the primordial germ-cells
contained in it. This goes on very rapidly during the eighth to
the eleventh days of incubation. The inner surface of the germinal epithelium, or ovigerous layer of the ovary, begins to form
 
 
 
THE URIXOGEXITAL SYSTEM
 
 
 
399
 
 
 
low irregular projections into the stroma, or the latter begins to
penetrate the ovigerous layer at irregular distances so as to
produce elevations. This condition is well illustrated in Fig.
229.
 
In the course of development the ovigerous layer continually
increases in thickness, and the projections into the stroma form
veritable cords of ovigerous tissue, which correspond to the
 
 
 
i^s^^iS:
 
 
 
^^
 
 
 
 
 
 
 
 
Fig. 230. — Cross-section of the ovary of a fledgling of Numenius arcuatus 3-4 days old. The germinal epithelium is below. (After
Hoffmann.)
s. c, Sexual cords.
 
cords of Pfltiger in the mammalian ovary. The cords carry
the primitive ova with them. The surface of the ovary also
begins to become lobulated by the extension of the stroma trabeculae. Successive stages in the growth and differentiation of
the primitive ova occur from the surface towards the inner ends
of the ovigerous strands. Fig. 230 represents a section through
 
 
 
400 THE DEVELOPIMENT OF THE CHICK
 
the ovary of a fledgling of Numenius arcuatus three or four days
old. The germinal epithelium covers the surface and is continuous with the ovigerous strands projecting far into the stroma.
The strands are broken up in the stroma into nests of cells;
next the germinal epithelium are found characteristic primitive ova, but in deeper situations the primitive ova are larger
and each is accompanied by a group of epithelial cells, which are
distinctly differentiated as granulosa cells of young follicles in
the deepest. Thus the young follicles arise by separation of
nests of cells from the ovigerous strands within the stroma;
each nest includes a young ovocyte and a group of epithelial
cells which arrange themselves in a single layer of cuboidal cells
around the ovocyte. On each side of the free border of the ovary
the embryonic state persists, and it is not known whether this
condition is maintained permanently, as in some reptiles, or
not.
 
The atrophy of the Wolffian body is much more complete in
the female than in the male; no part of it remains in a functional
condition, but the part corresponding to the epididymis of the
male remains as a rudiment, known as the epoophoron. It has
almost the same structure in young females as in young males,
but the rete cords uniting it with the ovary do not become tubular.
A rudiment of the non-sexual part of the Wolffian body is also
found in the hen between ovary and Iddney in the lateral part of
the mesovarium; it has been named the paroophoron.
 
Development of the Genital Ducts. The Wolffian Duct. The
origin and connections of the Wolffian ducts have been already
sufficiently described. In the male they are connected with the
seminiferous tubules by way of the epididymis, vasa efferentia,
and rete, and function as vasa deferentia exclusively, after degeneration of the mesonephros. Subsequently they become
somewhat convoluted, acquire muscular walls and a slight terminal dilatation. The details of these changes are not described
in the literature. In the female the Wolffian duct degenerates;
at what time is not stated in the literature, but presumably along
with the Wolffian body.
 
The Mullerian Duct. The Miillerian duct, or oviduct, is laid
down symmetrically on both sides in both male and female embryos; subsequently both right and left ]\Iiillerian ducts degenerate in the male; in the female the right duct degenerates, the
 
 
 
THE URIXOGEXITAL SYSTEM 401
 
left only remaining as the functional oviduct. We have now to
consider, therefore, (1) the origin of the ducts during the indifferent stage, and (2) their subsequent history in the male
and in the female.
 
The origin of the IMlillerian duct is preceded by the formation
of a strip of thickened peritoneum on the lateral and superior
face of the Wolffian body extending all the way to the cloaca
(cf. Fig. 220). This strip, which may be called the tubal ridge,
appears first at the anterior end of the Wolffian body on the
fourth da}", and rapidly differentiates backwards; it lies immediately external to the Wolffian duct. The anterior part of the
Miillerian duct arises as a groove-like invagination of the tubal
ridge at the cephalic end of the Wolffian body immediately
behind the external glomeruli of the pronephros. The hps of
this groove then approach and fuse on the fifth day, so as to form
a tube which soon separates from the ridge. This process, however, takes place in such a way as to leave the anterior end of
the tube open and this constitutes the coelomic aperture of the
oviduct, or ostium tuh(£ abdominale. Moreover, the closure of
the groove does not take place uniformly, and one or two openings into the Miillerian duct usually occur near the ostium on
the fifth clay. Typically, however, these soon close up, though
persistence of one of them may lead, as a rather rare abnormality,
to the occurrence of two ostia in the adult. There is no ground
for the view (see Balfour and Sedgwick) that the two or three
openings into the anterior end of the Miillerian duct correspond
to nephrostomes of the pronephros; they are situated too far
posteriorly and laterally to bear such an interpretation.
 
The anterior part of the Miillerian duct is thus formed by
folding from the epithelium of the tubal ridge; it constitutes a
short epithelial tube situated between the Wolffian duct and the
tubal ridge, ending blindly behind. The part thus formed is relatively short; the major portion is formed by elongation of the
anterior part, which slowly grows backwards between the Wolffian
duct and the tubal ridge, reaching the cloaca on the seventh day.
The growing point is solid and appears to act like a wedge separating the Wolffian duct and the tubal ridge, being thus closely
pressed against both, but apparently without receiving cells from
either. Balfour's view, that it grows by splitting off from the
Wolffian duct or at the expense of cells contributed by the latter,
 
 
 
402 THE DEVELOPAiEXT OF THE CHICK
 
has not been supported by subsequent investigators. A short
distance in front of the growing point the Mullerian duct receives
a kuiien, and mesenchyme presses in from above and below,
and forms a tunic of concentrically arranged cells around it
 
(Fig. 221).
 
The ]Mullerian duct thus begins to project above the surface
of the Wolffian body, and, as it does so, the thickened epithelium
of the tubal ridge becomes flat and similar to the adjacent peritoneum; whether it is used up in the formation of the mesenchymatous tunic of the epithelial Mullerian duct is not known.
Up to this time the development is similar in both sexes and on
both sides of the body.
 
In the male development of these ducts ceases on the eighth
day; retrogression begins immediately and is completed, or at
any rate far advanced, on the eleventh day. In this process the
epithelial wall disappears first, and its place is taken by cells
of mesenchymatous appearance, though it is not known that
transformation of one kind into the other takes place. Retrogression begins posteriorly and proceeds in the direction of the
head; the ostium is the last to disappear. The mesenchymatous
tunic shares in the process, so that the ridge is no longer found
(see Fig. 222). In the male the IMullerian ducts never open into
 
the cloaca.
 
In the female the development of the right Mullerian duct
ceases after the eighth day, and it soon begins to degenerate. Its
lumen disappears and it becomes relatively shorter, so that its
anterior end appears to slip back along the Wolffian body. On
the fifteenth day slight traces remain along its former course and
a small cavity in the region of the cloaca. It never obtains an
opening into the cloaca (Gasser).
 
With the degeneration of the anterior end of the Wolffian
body the ostium tubse abdominale comes to be attached by a
Ugament to the body-wall (Fig. 231); farther back the ligamentous attachment is to the Wolffian body.
 
The fimbriae begin to develop on the eighth day on both
sides in both sexes. It is only in the left oviduct of the female, however, that development proceeds farther, and differentiation into ostium, glandular part, and shell gland takes
place. This appears distinctly about the twelfth day. The
lower end expands to form the primordium of the shell
 
 
THE URIXOGEXITAL SYSTEM
 
 
 
403
 
 
 
gland at this time, but does not open into the cloaca. Indeed,
the opening is not established until after the hen is six months
old (Gasser.)
 
 
 
Aom
 
 
 
M'cj2
 
 
 
pl.C.r
 
 
 
/iec.p/j.e/iii'
 
 
 
o.r.a
 
 
 
 
 
 
 
Vcd.l.
 
 
 
Aar.v.c
 
 
 
Fig. 231. — Photograph of a cross-section of an embryo of 8 clays through the
 
ostia tubae abdominaha.
 
a. A. S., Xeck of abdominal air-sac. O. T. a., Ostium tubae abdominale.
M's't.ac, Accessory mesentery, pi. C. r., 1., Right and left pleural cavities.
Rec. pn. ent. r., Right pneumato-enteric recess. V. c. a. 1., Left anterior
vena cava. R., rib. Other abbreviations as before.
 
 
 
IV. The Suprarenal Capsules
 
The suprarenals of the hen are situated medial to the anterior
lobe of the kidney, in the neighborhood of the gonad and vena
cava inferior. They have a length of about 8-10 mm. The
substance consists of two kinds of cords of cells, known respectively as cortical and medullary cords, irregularly intermingled:
the so-called cortical cords make up the bulk of the substance,
and the medullary cords occur in the meshes of the cortical cords.
 
 
 
404 THE DEVELOPMENT OF THE CHICK
 
The terminology does not, therefore, describe well the topographical arrangement of the components; it was derived from
the condition found in many mammals, the cortical cords of the
birds corresponding to the cortical substance, and the medullary
cords to the medullary substance of mammals. The medullary
cords are often called phseochrome or chromaffin tissue on account
of the specific reaction of the constituent cells to chromic acid,
and their supposed genetic relation to tissue of similar composition
and reaction found in the carotid glands and other organs associated with the sympathetic system.
 
The embryonic history has been the subject of numerous
investigations, and has proved a particularly difficult topic, if
we are to judge from the variety of views propounded. Thus
for instance it has been maintained at various times: (1) that
cortical and medullary cords have a common origin from the
mesenchyme; (2) that they have a common origin from the
peritoneal epithehum; (3) that the origin of the cortical and
medullary cords is absolutely distinct, the former being derived
from the sexual cords by way of the capsules of the renal corpuscles and the latter from the sympathetic ganglia; (4) that
their origin is distinct, but that the cortical cords are derived
from ingrowths of the peritoneum, and the medullary cords from
sympathetic ganglia. The first view may be said now to be
definitely abandoned, and no one has definitely advocated a
common epithehal origin since Janosik (1883). Thus it may
be regarded as well estabUshed that the two components have
diverse origins, and it seems to the writer that the fourth view
above is the best supported. (See Poll and Soulie.) The comparative embryological investigations strongly support this
view.
 
Origin of the Cortical Cords. According to Soulie, the
cortical cords arise as proliferations of a special suprarenal zone
of the peritoneum adjacent to the anterior and dorsal part of
the germinal epithehum. This zone is distinguishable early on
the fourth day, and begins about half a millimeter behind the
glomeruH of the pronephros, extending about a millimeter in a
caudal direction. Proliferations of the peritoneal epithelium are
formed in this zone, and soon become detached as groups of
epithelial cells lying in the mesenchyme between the anterior
end of the Wolffian body and the aorta. Such proliferation con
 
 
THE URINOGEXITAL SYSTEM 405
 
tinues up to about the one hundredth hour or a httle later, and
a second stage in the development of the cortical cords then
begins: The cords grow rapidly and fill the space on the mediodorsal aspect of the AVolffian body, and then come secondarily
into relation with the renal corpuscles of the latter and the sexual
cords.
 
According to Semon and Hoffmann the relation thus established is a primary one, that is to say, that the cortical cords
arise from the same outgrowths of the capsules of the renal corpuscles that furnish the sexual cords. Rabl agrees essentially
with Soulie, and it seems probable that Semon and Hoffmann
have overlooked the first stages in the origin of the cortical cords
of the suprarenal corpuscles.
 
During the fifth, sixth, and seventh days there is a very
rapid increase of the cortical cords accompanied by a definite
circumscription of the organ from the surrounding mesenchyme;
however, no capsule is formed yet. The topography of the organ
on the eighth day is shown in Figs. 150 and 182. Whereas during
the fourth, fifth, and sixth days the arrangement of the cortical
cells is in masses rather than in cords, on the eighth day the
cords are well developed, in form cylindrical with radiating cells,
but no central lumen. The organ has become vascular, and the
vessels have the form of sinusoids, i.e., they are moulded on the
surface of the cords with no intervening mesenchyme.
 
Origin of the Medullary Cords. The medullary cords take
their origin unquestionably from cells of the sympathetic nervous system. During the growth of the latter towards the mesentery, groups of sympathetic cells are early established on or near
the dorso-median surface of the cortical cords (Fig. 226). The
ingrowth of the sympathetic medullary cords does not, however,
begin until about the eighth day. At this time there is a large
sympathetic ganglionic mass on the dorso-median surface of the
anterior end of the suprarenal, and strands of cells characterized
sharply by their large vesicular nuclei and granular contents
can be traced from the ganglion into the superficial part of the
suprarenal. These cells are precisely like the specific cells of
the ganglion, perhaps a little smaller, and without axones. On
the eleventh day these strands have penetrated through a full
third of the thickness of the suprarenal, and are still sharply
characterized, on the one hand by their resemblance to the
 
 
 
406 THE DEVELOPMENT OF THE CHICK
 
sympathetic ganglion cells, and on the other by their clear
differentiation from the cells of the cortical cords. These
occupy the relations characteristic of the differentiated medullary cords, and there can be httle doubt that they develop into
them.
 
 
 
CHAPTER XIV
THE SKELETON
 
I. General
 
From an embryological point of view, tlie bones of the body,
their associated cartilages, the ligaments that unite them together
in various ways, and the joints should be considered together,
as they have a common origin from certain aggregations of
mesenchyme. The main source of the latter is the series of
sclerotomes, but most of the bones of the skull are derived from
the unsegmented cephalic mesenchyme.
 
Most of the bones of the body pass through three stages in
their embryonic development: (1) a membranous or prechondral
stage, (2) a cartilaginous stage, (3) the stage of ossification.
Such bones are known as cartilage bones, for the reason that
they are preformed in cartilage. Many (see p. 433 for list) of
the bones of the skull, the clavicles and the uncinate processes of
the ribs do not pass through the stage of cartilage, but ossification takes place directly in the membrane; these are known as
membrane or covering bones. The ontogenetic stages of bone
formation parallel the phylogenetic stages, membrane preceding
cartilage, and the latter preceding bone in the taxonomic series.
Thus, in Amphioxus, the skeleton (excluding the notochord)
is membranous; in the lamprey eel it is partly membranous and
partly cartilaginous; in the selachia it is mainly cartilaginous; in
higher forms bone replaces cartilage to a greater or less degree.
The comparative study of membrane bones indicates that they
were primitively of dermal origin, and only secondarily grafted
on to the underlying cartilage to strengthen it. Thus the cartilage bones belong to an older category than the membrane
bones.
 
The so-called membranous or prechondral stage of the skeleton
is characterized simply by condensation of the mesenchyme.
Such condensations arise at various times and places described
 
407
 
 
 
408 THE DEVELOPMENT OF THE CHICK
 
beyond, and they often represent the primordia of several future
bony elements. In such an area the cells are more closely aggregated, the intercellular spaces are therefore smaller, and the
area stains more deeply than the surrounding mesenchyme.
There are, of course, stages of condensation in each case, from
the first vague and undefined areas shading off into the indifferent
mesenchyme, up to the time of cartilage or bone formation,
when the area is usually well defined. In most of the bones,
however, the process is not uniform in all parts; the growing
extremities may be in a membranous condition while cartilage
formation is found in intermediate locations and ossification has
begun in the original center of formation; so that all three stages
may be found in the primordium of a single bone {e.g., scapula).
Usually, however, the entire element is converted into cartilage
before ossification begins.
 
The formation of cartilage (chondrification) is brought about
by the secretion of a homogeneous matrix of a quite special character, which accumulates in the intercellular spaces, and thus
gradually separates the cells; and the latter become enclosed in
separate cavities of the matrix; when they multiply, new deposits
of matrix form between the daughter cells and separate them.
As the original membranous primordium becomes converted into
cartilage, the superficial cells flatten over the surface of the
cartilage and form a membrane, the perichondrium, which becomes the periosteum when ossification takes place.
 
The process of ossification in the long bones involves the following stages in the chick:
 
(1) Formation of Perichondral Bone. The perichondrium
deposits a layer of bone on the surface of the cartilage near its
center, thus forming a bony ring, which gradually lengthens into
a hollow cylinder by extending towards the ends of the cartilage.
This stage is well illustrated in Fig. 231 A and in the long bones
of Fig. 242; the bones of the wing and leg furnish particularly
good examples; the perichondral bone is naturally thickest in
the center of the shaft and thins towards the extremity of the
 
cartilages.
 
(2) Absorption of Cartilage. The matrix softens in the
center of the shaft and becomes mucous, thus liberating the
cartilage cells and transforming the cartilage into the fundamental tissue of the bone marrow. This begins about the tenth
 
 
 
THE SKELETON
 
 
 
409
 
 
 
day in the femur of the chick. The process extends towards the
ends, and faster at the periphery of the cartilage {i.e., next to
the perichondral bone) than in the center. In this way there
remain two terminal, cone-shaped cartilages, and the ends of the
cones project into the marrow cavity (Fig. 231 A).
 
(3) Calcification of Cartilage. Salts of lime are deposited in
the matrix of the cartilage at
 
the ends of the marrow cavity;
such cartilage is then removed
by osteoclasts, large multinucleated cells, of vascular endothelial origin, according to
Brachet (seventeenth or eighteenth day of incubation).
 
(4) Endochondral Ossification. Osteoblasts within the
marrow cavity deposit bone on
the surface of the rays of calcified cartilage that remain
between the places eaten out
by osteoclasts, and on the
irmer surface of the perichondral bone.
 
These processes gradually
extend towards the ends of
the bone, and there is never
any independent epiphysial
center of ossification in long
bones of birds, as there is in
mammals. The ends of the
bones remain cartilaginous
and provide for growth in length. Growth in diameter of the
bones takes place from the periosteum, and is accompanied by
enlargement of the marrow cavity, owing to simultaneous absorption of the bone from within. It is thus obvious that all of
the endochondral bone is removed from the shaft in course of
time; some remains in the spongy ends.
 
The details of the process of ossification will not be described
here, and it only remains to emphasize a few points. At a stage
shortly after the beginning of absorption of the cartilage in the
 
 
 
 
Fig. 231 A. — Longitudinal section of
the femur of a chick of 196 hours' incubation; semi-diagrammatic. (After
Brachet.)
 
art. Cart., Articular cartilage. C. C,
Calcified cartilage, end. B., Endochondral bone. M., Marrow cavity. P'ch.,
Perichondrium. P'os., Periosteum,
p'os. B., Periosteal bone. Z. Gr., Zone
of growth. Z. Pr., Zone of proliferation.
Z. R., Zone of resorption.
 
 
 
410 THE DEVELOPMENT OF THE CHICK
 
center of the shaft, the perichondral bone is invaded by capillary
vessels and connective tissue that break through into the cavity
formed by absorption; it is supposed by many that osteoblasts
from the periosteum penetrate at the same time. The marrow
of birds is derived, according to the best accounts, from the
original cartilage cells, which form the fundamental substance,
together with the intrusive blood-vessels and mesenchyme. The
endochondral osteoblasts are believed by some to be of endochondral origin (i.e., derived from cartilage cells), by others of
periosteal origin. For birds, the former view seems to be the
best supported.
 
In birds, calcification does not precede absorption of the
cartilage, as it does in mammals, until the greater part of the
marrow cavity is formed. The cones of cartilage, referred to
above, that are continuous with the articular cartilages, are
absorbed about ten days after hatching.
 
On the whole, perichondral ossification plays a more extensive
role in birds than in mammals. The endochondral bone formation begins relatively much later and is less extensive. The
bodies of the vertebrae, which ossify almost exclusively in an
endochondral fashion, form the main exception to this rule.
 
Ossification in membrane proceeds from bony spicules deposited between the cells in the formative center of any given
membrane bone. It spreads out from the center, the bony
spicules forming a network of extreme delicacy and beauty.
After a certain stage, the membrane bounding the surface becomes
a periosteum which deposits bone in dense layers. Thus a membrane bone consists of superficial layers of dense bone, enclosing
a spongy plate that represents the primitive bone before the
establishment of the periosteum.
 
The formation of bones proceeds from definite centers in all
three stages of their formation; thus we have centers of membrane formation, centers of chondrification and centers of ossification. Membranous centers expand by peripheral growth,
cartilage centers expand by the extension of cartilage formation
in the membrane from the original center of chondrification, and
bony centers expand in the original cartilage or membrane.
Several centers of chondrification may arise in a single primitive
membranous center; for instance, in the membranous stage, the
skeleton of the fore-limb and pectoral girdle is absolutely con
 
 
THE SKELETON 411
 
tinuoiis; cartilage centers then arise separately in different parts
for each of the bones: similarly for the hind-limbs and pelvic
girdle, etc. Separate centers of ossification may likewise appear
in a continuous embryonic cartilage, as for instance, in the base
of the skull or in the cartilaginous coraco-scapula, or ischioilium. Such centers may become separate bones or they may
subsequently fuse together. In the latter case, they may represent bones that were phylogenetically perfectly distinct elements,
as for instance, the prootic, epiotic, and opisthotic centers in
the cartilaginous otic capsule; or they may be of purely functional significance, as for instance, the separate ossifications in
the sternum of birds, or the epiphysial and diaphysial ossifications of the long bones of mammals. It is usually possible on
the basis of comparative anatomy to distinguish these two categories of ossification centers.
 
Phylogenetic reduction of the skeleton is also usually indicated in some manner in the embryonic history. Where elements
have completely disappeared in the ph3dogenic history, as for
instance, the missing digits of birds, they often appear as membrane formations in the embrvo, which then fade out without
reaching the stage of cartilage; if the latter stage is reached the
element usually fuses with some other and is therefore not really
missing, e.g., elements of the carpus and tarsus of birds (though
not all). But the ontogenetic reduction may go so far that
the missing elements are never distinguishable at any stage of
the embryonic history; thus, though the missing digits of birds
are indicated in the membranous stage, their component phalanges
are not indicated at all.
 
II. The Vertebral Column
 
The primordia of the vertebral column are the notochord
and sclerotomes. The former is the primitive axial support of
the body, both ontogenetically and phylogenetically. In both
components, notochord and sclerotomes, we may recognize a
cephalic and trunk portion. The notochord, as we have seen,
extends far into the head, and the sclerotomes of the first four
somites contribute to the formation of the occipital portion of
the skull. The cephalic parts are dealt with in the development
of the skull. The history of the notochord and sclerotomes will
be considered together, but we may note in advance that the
 
 
 
412 THE DEVELOPMENT OF THE CHICK
 
notochord is destined to be completely replaced by the bodies of
the vertebrae, derived from the sclerotomes.
 
The Sclerotomes and Vertebral Segmentation. The vertebral
segmentation does not agree with the primitive divisions of the
somites, but alternates with it; or in other words, the centers
of the vertebrae do not coincide with the centers of the original
somites, but with the intersomitic septa in which the segmental
arteries run. Thus each myotome extends over half of two
vertebral segments, and the spinal ganglia and nerves tend to
alternate with the vertebrae. It therefore happens that each myotome exerts traction on two vertebrae, obviously an advantageous
arrangement, and the spinal nerves lie opposite the intervertebral
foramina.
 
This arrangement is brought about by the development of
each vertebra from the caudal half of one sclerotome and the
cephalic half of the sclerotome immediately behind; parts of
two somites enter into the composition of each vertebra, as is
very obvious at an early stage: Fig. 232 represents a section
through the base of the tail of a chick embryo of ninety-six hours;
it is approximately frontal, but is inclined ventro-dorsally from
behind forwards. The original somites are indicated by the
myotomes and the segmental arteries. In the region of the
notochord one can plainly distinguish three parts to each
sclerotome, viz., (1) a narrow, median, or perichordal part
abutting on the notochord, in which no cUvisions occur either
within or between somites; (2) a caudal lateral cUvision distinguished by the denser aggregation of the cells from (3) the cephalic
division. Between the caudal and cephalic cUvisions of the sclerotome is a fissure (intervertebral fissure) which marks the boundary
of the future vertebrae. Each vertebra in fact arises from the
caudal component of one sclerotome and the cephalic component
of the sclerotome immediately behind. Between adjacent sclerotomes is the intersomitic septum containing the segmental artery.
If one follows these conditions back into successively earlier stages,
one finds that the intervertebral fissure arises from the primitive
somitic cavity, and that the distinction between caudal and
cephalic divisions of the sclerotome is marked continuously from a
very early stage by the presence of the intervertebral fissure and
the greater density of the caudal division, i.e., the cephalic component of each definitive vertebra.
 
 
 
THE SKELETOX
 
 
 
413
 
 
 
 
 
 
TT — ^5 — a « "o-w
 
 
 
 
 
 
'1 •^^•^-'o.ool
 
 
 
 
^/7 — ^ ^ifflii'
 
 
 
^
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
.«"»
 
 
 
 
 
 
, < r. ■,■
 
 
 
 
 
 
 
 
 
 
CdUd^C/ "^dl "■'5-S:^;
 
 
 
/y7/i:/^
 
 
 
 
 
 
 
7^^?l?
 
 
 
'»2g.' «>5.<' '• ^- .
 
 
 
 
 
 
 
.. °SS-,.
 
 
 
 
 
 
 
 
 
1 vs^-i.^-"^'":^^^-^^
 
 
 
 
 
5 'D
 
 
 
o v.
 
 
4^
 
 
 
■^s
 
 
 
 
 
 
y;7/j. /--^ XtCf"^ -fi-.sV^ -o. o " :
 
 
 
 
 
 
 
 
 
■'-r-,'fc'-V' •'»'£'';'■■'/<' '?<^ Co"© ^ -^ .li-a - - S.Jo
 
 
 
^ 6
 
 
 
 
 
~ ^ Ask ' S»Jo - , ^»
 
 
 
TK^r^
 
 
 
. .0^:^
 
 
 
 
 
 
 
^ «. . ', >^.-".,^e
 
 
 
«,,?rV.?:
 
 
 
^!.
 
 
 
"-J
 
 
 
Fig. 232.— Frontal section through the base of the tail of a chick
embryo of 96 hours. The anterior end of the section (above
in the figure) is at a higher plane than the posterior end.
caud. Scl., Caudal division of the sclerotome, ceph Scl Cephalic division of the sclerotome. Derm., Dermatome. Ep., Epidermis. Gn., Ganglion, int's. F., Intersomitic fissure int'v F
Intervertebral fissure. My., Mvotome. N'ch., Notochord Nt'
Neural tube, per'ch. Sh., Perichordal sheath, s. A., Segmental
artery.
 
 
 
414 THE DEVELOPMENT OF THE CHICK
 
Now, if one follows these components as they appear at successively higher levels in such a frontal section as Fig. 232, one
finds that the perichordal layer disappears in the region of the
neural tube, and that the spinal ganglia appear in the cephalic
division of the sclerotome, and almost completely replace it.
Thus the caudal division of the sclerotome is more extensive, as
well as denser, than the cephalic division.
 
In transverse sections one finds that the sclerotomic mesenchyme spreads towards the middle line and tends to fill all the
interspaces between the notochord and neural tube, on the one
hand, and the myotomes on the other. But there is no time at
which the sclerotome tissue of successive somites forms a continuous unsegmented mass in which the vertebral segmentation
appears secondarily, as maintained by Froriep, except in the thin
perichordal layer; on the contrary, successive sclerotomes and
vertebral components may be continuously distinguished, except
in the perichordal layer; and the fusion of caudal and cephalic
sclerotome halves to form single vertebrae may be continuously
followed. Thus, although the segmentation of the vertebrae is
with reference to the myotomes and ganglia, it is dependent
upon separation of original sclerotome halves, and not secondarily
produced in a continuous mass.
 
Summarizing the conditions at ninety-six hours, we may say
that the vertebrae are represented by a continuous perichordal
layer of rather loose mesenchvme and two mesenchvmatous
arches in each segment, that ascend from the perichordal layer
to the sides of the neural tube; in each segment the upper part
of the cephalic sclerotomic arch is occupied almost completely
by the spinal ganglion, but the caudal arch ascends higher, though
not to the dorsal edge of the neural tube. The cranial and caudal
arches of any segment represent halves of contiguous, not of the
same, definitive vertebra.
 
Membranous Stage of the Vertebrae. In the following or
membranous stage, the definitive segmentation of the vertebrae
is established, and the principal parts are laid down in the
membrane. These processes are essentially the same in all the
vertebrae, and the order of development is in the usual anteroposterior direction. As regards the establishment of the vertebral segments: Figs. 233 and 234 represent frontal sections
through the same vertebral primordia at different levels from
 
 
 
THE SKELETON
 
 
 
415
 
 
 
the thoracic region of a five-day chick. The notochord is
slightly constricted intervertebrally, and the position of the
intersegmental artery, of the myotomes and nerves, shows that
each vertebral segment is made up of two components representing succeeding sclerotomes. In the region of the neural
arches (Fig. 234) the line of union of cranial and caudal vertebral
components is indicated by a slight external indentation at the
place of union, and by the arrangement of the nuclei on each
side of the plane of union.
 
 
 
Cduc/.Sc/
ceph.Sc'.
 
//
 
 
• » ." '5',*' 'Ir "-V^ ^i*^-^-* -'.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
:^^V:. .
 
 
 
 
 
 
 
 
 
Mj/-"^^^
 
 
 
ceph Sci.- ''^
 
 
 
^ \ . o c
 
 
y^i-
 
 
.y.y^;{^^> -jt^.> " /^^.^
 
 
 
 
 
 
 
 
 
 
Fig. 233. — Frontal section through the notochord and pri
mordia of two vertebrae of a 5-day chick; thoracic region.
 
Note intervertebral constrictions of the notochord. The
 
anterior end of the section is above.
 
N., Spinal nerve. Symp., Part of sympathetic cord. v. C,
Region of pleurocentrum, in which the formation of cartilage
 
 
 
has hegun.
 
 
 
Other abbreviations as in Fig. 232.
 
 
 
The parts of the vertebrae formed in the membranous stage
are as follows: (1) The vertebral body is formed by tissue of
both vertebral components that grows around the perichordal
sheath; (2) a membranous process (neural arch) extends from
the vertebral body dorsally at the sides of the neural canal; but
the right and left arches do not yet unite dorsally; (3) a lateral
or costal process extends out laterally and caudally (Fig. 233)
from the vertebral body between the successive myotomes.
 
The union of the right and left cephalic vertebral components
 
 
 
416
 
 
 
THE DEVELOPMENT OF THE CHICK
 
 
 
(caudal sclerotome halves) beneath the notochorcl is known as
the subnotochordal bar (Froriep). It forms earlier than the
remainder of the body of the vertebra and during the membranous
stage is thicker, thus forming a ventral projection at the cephalic
end of the vertebral body that is very conspicuous (Fig. 235).
 
 
 
caud-Se/.
 
 
 
 
 
 
 
 
 
 
 
 
 
caud Se/
 
s.A
cep/?.'5c/
 
 
 
 
 
 
 
cac/f^ ^C/
 
 
 
 
 
 
 
 
jtfy:
 
 
 
 
 
 
 
 
 
i A^.V
 
 
 
to ei\--^^ i-
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
»",-^*
•c,-^
 
 
 
>p.
 
 
 
 
 
 
S-li
 
 
 
Fig. 234. — Frontal section including the same vertebral primordia as Fig. 233, at a higher level through the neural arches,
a. C, Anterior commissure of the spinal cord. v. R., Ventral root of spinal nerve. Other abbreviations as before (Fig;.
232).
 
 
 
It chondrifies separately from the vertebral body and earlier.
Except in the case of the first vertebra it fuses subsequently
with the remainder of the vertebral body, and disappears as
 
 
 
THE SKELETOX
 
 
 
417
 
 
 
a separate component. Schauinsland has interpreted it as the
homologue of the haemal arches of reptilia {e.g., Sphenodon).
 
The membrane represents not only the future bony parts
but the ligaments and periosteum as well. Hence we find that
the successive membranous vertebrae are not separate structures
but are united by membrane, i.e., condensed mesenchyme, and
are distinguishable from the future ligaments at first only by
greater condensation. In the stage of Fig. 233, chondrification
has already begun in the vertebral body, hence there is a sharp
 
 
 
/v'a
 
 
 
Fig. 235. — Median sagittal section of the cervical region at
 
the end of the sixth day of incubation. (After Froriep.) x 40.
 
b. C, Basis cranii. iV. L. 1, 2, 3, First, second, and third
intervertebral ligaments, s. n. b. 1, 2, 3, 4, First, second, third,
and fourth subnotochordal bars (hypocentra). v. C. 3, 4,
Pleurocentra of third and fourth vertebrae.
 
 
 
distinction in this region l^etween the vertebral bod}^ and intervertebral discs. The centers of chondrification, however, grade
into the membranous costal processes and neural arches.
 
The vertebral segmentation has now become predominant as
contrasted with the primitive somitic.
 
The development of the vertebrae during the fifth day comprises: (1) Fusion of successive caudal and cephalic divisions of
 
 
 
418 THE DEVELOPMENT OF THE CHICK
 
the sclerotomes to form the definitive vertebrae; (2) union of the
cephaUc vertebral components beneath the notochord to form the
subnotochordal bar; (3) origin of the membranous vertebral
bodies and of the neural arch and costal processes.
 
Chondrification, or development of cartilage, sets in from the
following centers in each vertebra: (1) the cephalic neural arches
and subnotochordal bar, forming a horseshoe-shaped cartilage
at the cephalic end of each vertebra; (2) and (3) right and left
centers in the body of each vertebra behind the subnotochordal
bar, which soon fuse around the notochord; (the subnotochordal
bar probably corresponds to the hypocentrum, and the lateral
centers (2 and 3) to the pleurocentra of palaeontologists) ; (4) and
(5) centers in each costal process (Figs. 235 and 236). These
centers are at first separated by membrane, l)ut except in the
case of the costal processes, which form the ribs, the cartilage
centers flow together. The neural arches end in membrane
which gradually extends dcrsally around the upper part of the
neural tube, finally uniting above with the corresponding arches
of the other side to form the memhrana reuniens. The chondrification follows the extension of the membrane. During this
time the transverse processes of the neural arch and the zygopophyses are likewise formed as extensions of the membrane.
 
The distinction that some authors make between a primary
vertebral l^ody formed ]:)y chondrification within the perichordal
sheath, and a secondary vertebral body formed by the basal
ends of the arches surrounding the primary, is not a clear one
in the case of the chick.
 
On the seventh and eighth days the process of chondrification extends into all parts of the vertebra; the entire vertebra
is, in fact, laid down in cartilage on the eighth da}', although the
neural spine is somewhat membranous. Fig. 237 shows the
right side of four trunk vertebrae of an eight-day chick, prepared
according to the methylene b,lue method of Van Wijhe. The
 
 
 
Fig. 236. — Frontal section of the vertebral column and neighboring structures of a 6-day chick. Upper thoracic region. Note separate centers
of chondrification of the neural arch, centrum, and costal processes. Anterior end of section above.
B. n. A., Base of neural arch. br. N. 1, 2, 3, First, second, and third
brachial nerves. Cp. R., Capitulum of rib. iv. D., Intervertebral disc.
Mu., Muscles. N. A., Neural arch. T. R., Tuberculum of rib. V. C, Centrum of vertebra. Other abbreviations as before.
 
 
 
THE SKELETON
 
 
 
419
 
 
 
 
--jV.D.
 
 
 
420
 
 
 
THE DEVELOPMENT OF THE CHICK
 
 
 
notochord runs continuously through the centra of the four
vertebrae shown. It is constricted intra vertebrally and expanded
intervertebrally, so that the vertebral bodies are amphicoelous.
The intervertebral discs are not shown. A pre- and postzygapophysis is formed on each arch. It is by no means certain that the
parts separated by the clear streak shown in the figure extending
through centra and arches correspond to the sclerotomal components of the primitive vertebrae, though this was the interpretation of Schauinsland as shown in the figure; further
study seems necessary to determine the exact relations of the
primitive sclerotomal components to the parts of the definitive
vertebra. The successive vertebrae have persistent membranous
 
 
 
 
Fig. 237. — The right side of four bisected vertebrse of the trunk
 
of an 8-day chick. (After Schauinsland.)
 
caud. V. A., Caudal division of vertebral arch. ceph. v. A.,
Cephalic division of vertebral arch. N'ch., Xotochord.
 
connections in the regions of the neural spines, zygapophyses
and centra. These are shown in Figs. 238 and 239 (cf. also
Fig. 150) ; they are continuous with the perichondrium and all
are derived from unchondrified parts of the original membranous vertebrae.
 
Atlas and Axis (epistropheus). The first and second vertebrae agree with the others in the membranous stage. But, when
chondrification sets in, the hypochordal bar of the first vertebra does
not fuse with the body, but remains separate and forms its floor
(Figs. 238 and 239). The body of the first vertebra chondrifies
separately and is attached by membrane to the anterior end of
the body of the second vertebra, representing in fact the odontoid process of the latter. It has later a separate center of ossification, but fuses subsequently wdth the body of the second
vertebra, forming the odondoid process (Fig. 240).
 
 
 
THE SKELETON
 
 
 
421
 
 
 
Formation of Vertebral Articulations. In the course of development the intervertebral discs differentiate into a peripheral intervertebral ligament and a central suspensory ligament which at first
contains remains of the notochord. There is a synovial cavity
between the intervertebral and suspensory ligaments. This differentiation takes place by a process of loosening and resorption
 
 
 
 
Fig. 238. — Median sagittal section of the basis
 
cranii and first three vertebral centra of an
 
8-day chick.
 
B. C, Basi-cranial cartilage, iv. D. 1, 2, 3, 4,
 
First, second, third, and fourth intervertebral
 
discs. N. T., Floor of neural tube. s. n. b. 1, 2,
 
First and second subnotochordal bars. V. C.
 
1, 2, 3, First, second, and third pleurocentra.
 
of cells just external to the perichordal sheath (Fig. 241). The intervertebral ligament takes the form of paired, fibrous menisci, or, in
other words, the intervertebral ligaments are incomplete around
the bodies of the vertebrae dorsally and ventrally (Schwarck).
Ossification is well advanced in the clavicles, long bones,
 
 
 
422
 
 
 
THE DEVELOPMENT OF THE CHICK
 
 
 
and membrane bones of the skull before it begins in the vertebrae.
It takes place in antero-posterior order, so that a series of stages
may be followed in a single embryo (cf. Fig. 242). There are
three main centers for each vertebra, viz., one in the body and
one in each neural arch. The ossification of the centrum is almost
 
 
 
 
 
 
—Medobl
 
 
 
H'9^1112
 
 
 
.f
 
 
 
'." " ">• '•'ti't-'
 
 
 
 
 
 
 
 
oC-l.o
 
 
 
 
 
 
 
-^mk
 
 
 
 
 
 
 
 
 
T/ltl
rceiMS.
 
 
 
, i: f 'j'f' , ., f , n yc
 
 
 
 
 
 
■yj
 
 
 
.-^,4^V^J^/?^.^^
 
 
 
UJ:
 
 
 
 
 
 
5p.G/i2-Fi
 
 
 
 
^■>'i
 
 
 
'RVd.
 
 
 
-+,-'
 
 
 
'-■'oi-.S'"'- (,.'■>•,'■ I ■
 
 
 
5i/mp.Cn
 
 
 
-r/^V4
 
 
 
 
 
 
PiQ 239. — Lateral sagittal section of the same vertebrse (as in Fig.
 
238).
At 1, 2, Floor and roof of atlas. B. C, Basis cranii. Cerv. n. 1, 2,
First and second cervical nerves. Med. Obi., Medulla oblongata.
R. V. 2, 3, 4, Ribs of the second, third, and fourth vertebrse. V . A.
2, 3, Arches of the second and third vertebrse.
XII 2, Second root of hypoglossus.
 
entirely endochondral, though traces of perichondral ossification
may be found on the ventral and dorsal surfaces of each centrum
before the endochondral ossification sets in. The perichondral
centers soon cease activity. The endochondral centers arise
just outside the perichordal sheath near the center of each vertebra on each side of the middle line, but soon fuse around the
 
 
 
THE SKELETON
 
 
 
423
 
 
 
notochord, and rapidly spread in all directions, but particularly
towards the surface, leaving cartilaginous ends (Fig. 241). The
notochord is gradually reduced and exhibits two constrictions
 
 
 
 
Fig. 240. — The first cervical vertebrae of a young
 
embryo of Haliplana fuliginosa. (After Schauins
land.)
 
s.n.b. 1,2, First and second subnotochordal bars.
R. 3, 4, 5, 6, Ribs of the third, fourth, fifth, and sixth
cervical vertebrae.
 
 
 
and three enlargements within each centrum. The main enlargement occupies the center and the two smaller swellings the
cartilaginous ends, the constriction occurring at the junction of
the ossified areas and cartilaginous ends (Fig. 241).
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
J
 
 
 
Fig. 241. — Section through the body of a cervical vertebra of a chick embryo of about 12
days. (After Schwarck.)
 
1, Endochondral ossification. 2, Articular
cartilages. 3, Notochord. 4, Loosening of cells
of the intervertebral disc, forming a synovial
cavity. 5, Periosteum. 6, Ligamentum suspensorium surrounding the notochord.
 
 
 
424 THE DEVELOPMENT OF THE CHICK
 
The centers of ossification in the neural arches arise from
tlie perichondrium a short distance above the body of the vertebra, and form bony rings about the cartilaginous arch. They
gradually extend into all the processes of the neural arch. Thus
the neural arches are separated from the vertebral centra by a
disc of cartilage which is, however, finally ossified, fusing the
arches and centra. At what time this occurs, and at what
time endochondral ossification begins in the arches, is not
known exactly for the chick.
 
The vertebral column of birds is characterized by an extensive
secondary process of coalescence of vertebrae. Thus the two
original sacral vertebra? coalesce with a considerable number of
vertebrae, both in front and behind, to form an extensive basis
of support for the long iliac bones. The definitive sacrum may
be divided into an intermediate primary portion composed of
two vertebrge, an anterior lumbar portion, and a posterior caudal
portion. The development of these fusions has not been, apparently, worked out in detail for the chick. The bony centers are
all separate on the sixteenth day of incubation (cf. Fig. 249).
Similarly, the terminal caudal vertebrae fuse to form the so-called
pygostyle, which furnishes a basis of support for the tail feathers.
 
III. Development of the Ribs and Sternal Apparatus
In the membranous stage of the vertebral column, all of the
trunk vertebra? possess membranous costal processes the subsequent history of which is different in different regions. In the
cervical region these remain relatively short, and subsequently
acquire independent centers of chondrification and ossification.
The last two cervical ribs, however, acquire considerable length.
In the region of the thorax, the membranous costal processes
grow ventralward between the successive myotomes and finally
unite in the formation of the sternum (q.v.). In the lumbar and
sacral regions the membranous costal processes remain short.
The primary costal process is an outgrowth of the membranous
centrum, corresponding in position to the capitulum of the
definitive ril). The tuberculum arises from the primary costal
process while the latter is still in the membranous condition and
grows dorsal ward to unite with the neural arch in the region of
the transverse process. (See Fig. 236.)
 
The centers of chondrification and ossification of the typical
 
 
 
THE SKELETON 425
 
ribs (cervical and thoracic) arise a short distance lateral to the
vertebral centers, with which they are connected only by the
intervening membrane, which forms the vertebro-costal ligaments. Chondrification then proceeds distally.
 
The cervical ribs chondrify from a single center. The thoracic
ribs have two centers of chondrification; a proximal one, corresponding to the vertebral division of the rib. and a distal one
corresponding to the sternal division. The lumbar and sacral
membranous costal processes do not chondrify separately from
the vertebral bodies; if they persist at all, therefore, they appear
as processes of the vertebrae, and are not considered further.
 
In the fowl the atlas does not bear ribs, and in the embryo the primary
costal processes of this vertebra do not chondrify. The second to the
fourteenth vertebrae bear short ribs, with capitulum and tuberculum
bounding the vertebrarterial canal. The fourteenth is the shortest of
the cervical series. The fifteenth and sixteenth vertebrae bear relatively
long ribs, but, as these do not reach the sternum, they are classed as
cervical. The entire embryonic history, however, puts them in the
same class as the following sternal ribs; on an embryological basis they
should be classed as incomplete thoracic ribs. They possess no sternal
division, but the posterior one has an uncinate process like the true thoracal ribs. The following five pairs of ribs (vertebrae 17-21) possess
vertebral and sternal portions, but the last one fails to reach the sternal
rib in front of it.
 
The vertebral and sternal portions of the true thoracal ribs
meet at about a right angle in a membranous joint. This bend
is indicated in the membranous stage of the ribs.
 
The membranous ribs growing downwards and backwards
in the wall of the thorax make a sudden bend forward, and their
distal extremities fuse (seven and eight days) in a common membranous expansion (primordium of the sternum), which, however,
is separated from the corresponding expansion of the opposite
side bv a considerable area of the body-wall.
 
The vertebral and sternal portions of the ribs ossify separately;
the ossification of the ribs is exclusively perichondral up to at
least the sixteenth day (cf. Fig. 242).
 
The uncinate processes were not formed in any of the embryos
studied. Apparently they arise as separate membranous ossifications after hatching.
 
The sternum takes its origin from a pair of membranous expan
 
 
426
 
 
 
THE DEVELOPMENT OF THE CHICK
 
 
 
sions formed by the fusion of the distal ends of the first four
true thoracal ribs; the fifth pair of thoracal ribs does not take
part in the formation of the sternum. The sternum thus arises
as two distinct halves, which lie at first in the wall of the thorax
at the posterior end of the pericardial cavity (eight days). The
greatest extension of the sternal primordia is do rso- ventral, the
 
 
 
 
Fig. 242. — Photograph of the skeleton of a 13-day
chick embryo. Prepared by the potash method.
(Preparation and photograph by Roy L. Moodie.)
1, Premaxilla. 2, NasaL 3, lachrymaL 4, Parasphenoid. 5, Frontal. 6, Squamosal. 7, Parietal.
8, Exoccipital. 9, Cervical rib. 10, Coracoid. 11,
Scapula. 12, Humerus. 13, Ilium. 14, Ischium. 15,
Pubis. 16, Metatarsus. 17, Tibiofibula. 18, Palatine. 19, Jugal. 20, Maxilla. 21, Clavicle.
 
ventral extremities corresponding to the anterior end of the definitive sternum, which is formed by concrescence of the lateral halves
in the middle line beginning at the anterior end. The concrescence
 
 
 
THE SKELETON 427
 
then proceeds posteriorly, as the dorsal ends of the priraordia
rotate backwards and downwards towards the middle line.
 
Although there are two lateral centers of chondrification,
these soon fuse. The carina arises as a median projection very
soon after concrescence in any region, and progresses backwards,
rapidly following the concrescence. There is, therefore, no stage
in which the entire sternum of the chick is ratite, though this
condition exists immediately after concrescence in any region.
The various outgrowths of the sternum (episternal process, anterolateral and abdominal processes), arise as processes of the membranous sternum and do not appear to have independent centers
of chondrification.
 
The sternum ossifies from five centers, viz., a median anterior
center and paired centers in the antero-lateral and abdominal
processes. The last appear about the seventeenth day of incubation. On the nineteenth day a point of ossification appears
at the base of the anterior end of the keel. At hatching centers
also appear in the antero-lateral processes. The centers gradually
extend, but do not completely fuse together until about the third
month. The posterior end of the median division of the sternum
remains cartilaginous for a much longer period. In the duck
and many other birds there are only two lateral centers of ossification; the existence of five centers in the chick is, therefore,
probably not a primitive condition.
 
IV. Development of the Skull
 
The skull arises in adaptation to the component organs of
the head, viz., the brain, the sense organs (nose, eye, and ear)
and cephalic visceral organs (oral cavity and pharynx); it thus
consists primarily of a case for the brain, capsules for the sense
organs, and skeletal bars developed in connection with the margins of the mouth and the visceral arches. In the chick,
the primordia of the auditory and olfactory capsules are continuous ab initio with the primordial cranium; the protecting coat
of the eye (sclera) never forms part of the skull. Therefore, we
may consider the development of the skull in two sections, first
the dorsal division associated with brain and sense organs (neurocranium), and second, the visceral division or splanchnocranium.
Although the investment of the eyes forms no part of the skull,
yet the eyes exert an immense effect on the form of the skull.
 
 
 
428 THE DEVELOPMENT OF THE CHICK
 
Development of the Cartilaginous or Primordial Cranium.
 
(1) The Neurocranium. The neurocranium is derived from the
mesenchyme of the head, the origin of which has been described
previously. The mesenchyme gradually increases in amount and
forms a complete investment for the internal organs of the head.
It is not all destined, however, to take part in the formation of
the skeleton, for the most external portion forms the derma and
subdermal tissue; and, internal to the skeletogenous layer, the
membranes of the brain and of the auditory labyrinth, etc., are
formed from the same mesenchyme.
 
The notochord extends forward in the head to the hypophysis
(Figs. 67, 88, etc.), and furnishes a basis for division of the
neurocranium into chordal and prechordal regions. Within the
chordal division again, we may distinguish pre-otic, otic, and
post-otic regions according as they are placed in front of, around,
or behind the auditory sac. The part of the postotic region
behind the vagus nerve is the only part of the neurocranium
that is primarily segmental in origin. The sclerotomes of the
first four somites (Figs. 63 and 117) form this part of the skull;
and at least three neural arches, homodynamous with the vertebral arches, are formed in an early stage, but fuse together while
still membranous, leaving only the two pairs of foramina of the
twelfth cranial nerve as evidence of the former segmentation. It
is also stated that membranous costal processes are found in
connection with these arches, but they soon disappear without
 
chondrifying.
 
The primordial neurocranium is performed in cartilage and
corresponds morphologically to the cranium of cartilaginous
fishes. However, it never forms a complete investment of the
brain; except in the region of the tectum synoticum it is wide
open dorsally and laterally. It is subsequently replaced by
bone to a very great extent, and is completed and reinforced
by numerous membrane bones.
 
The neurocranium takes its origin from two quite distinct
primordia situated below the brain, viz., the parachordals and
the trabecular. The former develop on each side of and around
the notochord, being situated, therefore, behind the cranial
flexure and beneath the mid- and hind-brain; the trabeculae are
prechordal in position, being situated beneath the twixt-brain
and cerebral hemispheres, and extending forward through the
 
 
 
THE SKELETON 429
 
interorbital region to the olfactory sacs. It is obvious, therefore,
that the parachordals and trabeculse must form with relation to
one another the angle defined by the cranial flexure.
 
The parachordals appear in fishes as paired structures on
either side of the notochord, uniting secondarily around the
latter; but in the chick the perichordal portion is formed at the
same time as the thicker lateral portions, so that the parachordals
exist in the form of an unpaired basilar plate from the first. The
trabeculae are at first paired (in the earliest membranous condition), but soon fuse in front, while the posterior ends form a pair
of curved limbs (fenestra hypophyseos) that surrounds the infundibulum and hypophysis, and joins the basilar plate behind the
latter. At the same time that the parachordals and trabeculae
are formed by condensations of mesenchyme, the latter condenses also around the auditory sacs and olfactory pits in direct
continuity with the parachordals and trabeculae respectively; so
that the auditory and olfactory capsules are in direct continuity
with the base of the neurocranium from the beginning.
 
Chondrification begins in the primordial cranium about the
sixth day; it appears first near the middle line on each side, and
extends out laterally. Somewhat distinct centers corresponding
to the occipital sclerotomes may be found in some birds, but
they soon run together, and the entire neurocranium forms a
continuous mass of cartilage (sixth, seventh, and eighth days).
 
During this process the trabecular region increases greatly in
length simultaneouslv with the outgrowth of the facial region,
and the angle defined by the cranial flexure becomes thus apparently reduced. The posterior border of the fenestra hypophyseos
marks the boundary between the basilar plate and trabecular
region.
 
In the region of the basilar plate the following changes take
place: (1) in the post-otic or occipital region a dorso-lateral
extension (Fig. 244) fuses with the hinder portion of the otic
capsule, thus defining an opening that leads from the region of
the cavity of the middle ear into the cranial cavity (fissure metotica). This expansion is pierced by the foramina of the ninth
tenth and eleventh nerves. (2) The otic region becomes greatly
expanded by the enlargement of the membranous labyrinth. The
cochlear process grows ventrally and towards the middle line and
thus invades the original parachordal region (Fig. 168). The
 
 
 
430 THE DEVELOPMENT OF THE CHICK
 
posterior region of the otic capsule expands dorsally above the
hind-brain, and forms a bridge of cartilage extending from one
capsule to the other, known as the tectum synoticum (Fig. 244,
33). (3) The preotic region expands laterally and dorsally in
the form of a wide plate (alisphenoidal plate) which is expanded
transversely, and thus possesses an anterior face bounding the
orbit posteriorly and a posterior face forming part of the anterior
wall of the cranial cavity. This plate arises first between the
ophthalmic and maxillo-mandibular branches of the trigeminus,
and subsequently sends a process over the latter that fuses with
the anterior face of the otic capsule, thus establishing the foramen
prooticum.
 
For an account of numerous lesser changes, the student is referred
to Gaupp (1905), and the special literature (especially Parker, 1869).
The various foramina for the fifth to the twelfth cranial nerves are
defined during the process of chondrification ; the majority of these are
shown in the figures.
 
The trabecular region may be divided into interorbital and
ethmoidal (nasal) regions. The basis of the skeleton in this
region is formed by the trabecule alread}^ described. The median
plate formed by fusion of the trabeculse extends from the pituitary
space (fenestra hypophyseos) to the tip of the head; a high median
keel-like plate develops in the interorbital and internasal regions
 
Fig. 243. — Skull of an embryo of 65 mm. length; right side. Membrane
bones in yellow. Cartilage in blue. (Drawn from the model of W. Tonkoff ;
made by Ziegler.)
 
Fig. 244. — View of the base of the same model.
 
24.3-244. — 1, Squamosum. 2, Parietale. 3, Capsula auditiva. 4, Capsula auditiva (cochlear part). 5, Fissura metotica. 6, Epibranchial cartilage.
7, Sphenolateral plate. 8, Foramen prooticum. 9, Columella. 10. Otic process of quadratum. 11, Basitemporal (postero-lateral part of the parasphenoid).
12, Articular end of Meckel's cartilage. 13, Angulare. 14, Supra-angulare. 15,
Dentale. 16, Skeleton of tongue. 17, Pterygoid. 18, Palatine. 19, Rostrum
of parasphenoid. 20, Quadrato-jugal. 21, Jugal (zygomaticum). 22, Vomer.
23, Maxilla. 24, Premaxilla. 25, Anterior turbinal. 26, Posterior turbinal.
27, Nasale. 28, Prefrontal (lachrymale). 29, Antorbital plate. 30, Interorbital foramen. 31, Interorbital septum. 32,Frontale. 33, Tectum synoticum.
34, Foramen magnum. 35, Prenasal cartilage. 36, Orbital process of quadrate. 37, Articular process of Quadrate. 38. Fenestra basicranialis posterior.
39, Chorda. IX, Foramen glossopharyngei. X, Foramen vagi. XII, Foramina hypoglossei.
 
Fig. 245. — Visceral skeleton of the same model.
 
1, Dentale. 2, Operculare. 3, Angulare. 4, Supra-angulare. 5. Meckel's
cartilage. 6, Entoglossum (cerato-hyal). 7, Copula (1). 8, Pharyngobranchial (1). 9, Epibranchial. 10, Copula (2),
 
 
 
3?
 
 
 
30
 
 
 
3^y
 
 
 
 
f/g 243
 
 
 
 
 
f/"g t45
 
 
 
T,^
 
 
a4^
 
 
 
THE SKELETON 431
 
and fuses with the trabeculse, forming the septum interorbitale
and septum nasi (Fig. 243). The free posterior border of this
plate hes in front of the optic nerves; an interorbital aperture
arises in tlie plate secondarily (Fig. 243).
 
In the ethmoidal region the septum nasi arises as an anterior
continuation of the interorbital plate; and the trabecular plate
is continued forward as a prenasal cartilage in front of the olfactory sacs. Curved, or more or less rolled, plates of cartilage
develop in the axis of the superior, middle, and inferior turbinals
(see olfactory organ), and these are continuous with the lateral
wall of the olfactory capsules, which in its turn arises from the
dorsal border of the septum nasi (Figs. 243 and 244).
 
(2) The Origin of the Visceral Chondrocranium (Cartilaginous
Splanchnocranium) . The visceral portion of the cartilaginous
skull arises primarily in connection with the arches that bound
the cephalic portion of the alimentary tract, viz., oral cavity
and pharynx. In the chick, cartilaginous bars are formed in
the mandibular arch, hyoid arch, and third visceral arch. In
fishes, the posterior visceral arches also have an axial skeleton,
but hi the chick the mesenchyme of these arches does not develop
to the stage of cartilage formation. The elements of these arches
are primarily quite distinct. The upper ends of the mandibular
and hyoid skeletal arches are attached to the skull; and the lower
ends of the three arches concerned meet in the middle line. Two
medial elements or copulse are formed in the floor of the throat,
one behind the angle of the hyoid arch, and one behind the
third visceral arch (Fig. 245).
 
Mandibular Arch. Two skeletal elements arise in the mandibular arch on each side, a proximal one (the palato-quadrate) and a distal one (Meckel's cartilage). The former is
relatively compressed, and the latter an elongated element (Fig.
243, 10). The palato-quadrate lies external to the antero-vertral part of the auchtory capsule, and soon develops a triradiate
form. The processes are: the processus oticus, which applies
itself to the auditory capsule, the processus articidaris, which
furnishes the articulation for the lower jaw, and the processus
orhitalis, Avhich is directed anteromedially towards the orbit.
A small nodule of cartilage of unknown significance lies above
the junction of the processus oticus and otic labyrinth. Meckel's
cartilage is the primary skeleton of the lower jaw, corresponding
 
 
 
432 THE DEVELOPMENT OF THE CHICK
 
to the definitive lower jaw of selachians. It consists of two
rods of cartilage in the rami of the mandibular arch, which articulate proximally with the processus articularis of the palatoquadrate cartilage,, and meet distally at the symphysis of the
lower jaw. The form of the articulation of the lower jaw is early
defined in the cartilage (seven to eight days).
 
Hyoid Arch. The skeletal elements of the hyoid arch consist of
proximal and distal pieces (with reference to the neurocranium)
which have no connection at any time. The former are destined to
form the columella, and the latter parts of the hyoid apparatus.
The columella apparently includes two elements (in Tinnunculus
according to Suschkin, quoted from Gaupp) : a dorsal element,
interpreted as hyomandibular, in contact with the wall of the
otic capsule, and a small element (stylohyal) beneath the former.
The two elements fuse to form the columella, the upper end of
which is shown in Fig. 168. The stapedial plate (operculum of
the columella) is stated to arise in Tinnunculus from the wall
of the otic capsule, being cut out by circular cartilage resorption
and fused to the columella.
 
The distal elements of the hyoid arch consist of (1) a pair
of ceratohyals, which subsequently fuse in the middle line to
form the entoglossal cartilage, the proximal ends remaining free as
the lesser cornua of the hyoid, and (2) a median unpaired piece
(copula I or basihyal) behind the united ceratohyals (Fig. 245).
 
First Branchial Arch. The skeletal elements of the third visceral
(first branchial) arch are much more extensive than those of the
hyoid arch. They are laid down as paired cerato- and epi-branchial
cartilages on each side, and an unpaired copula II (basibranchial I)
in the floor of the pharynx, in the angle of the other elements
(Fig. 245). The cerato- and epibranchials increase greatly in
length, and form the long curved elements (greater cornua) of the
hyoid, which attain an extraordinary development in many birds.
 
Ossification of the Skull. The bones of the skull are of two
kinds as to origin: (1) those that arise in the primordial cranium,
and thus replace cartilage (cartilage bones or replacement bones),
and (2) those that arise by direct ossification of membrane (membrane or covering bones).
 
The cartilage bones of the bird's skull are: (a) in the occipital
region; the basioccipital, two exoccipitals, and the supraoccipitals; {h) in the otic region: prootic, epiotic, and opisthotic;
 
 
 
THE SKELETON 433
 
(c) in the orbital region: the basisphenoid, the orbitosphenoids,
the ahsphenoids and ossifications of the interorbital septum; (d) in
the ethmoidal region the bony ethmoidal skeleton; (e) the palatoquadrate cartilage furnishes the quadrate bone; (/) a proximal
ossification, the articulare, arises in Meckel's cartilage and fuses
later with membrane bones; (g) the upper part of the hyoid arch
furnishes the columella, and the ceratohyals the os entoglossum;
(h) the cerato- and epibranchials ossify independently, as also
do the two copulse. (See Figs. 243, 244 and 245.)
 
The membrane bones of the skull are: (a) in the region of the
cranium proper: parietals, frontals, squamosals; (6) in the facial
region: lachrymals, nasals, premaxillae, maxillae, jugals, quadrato-jugals, pterygoids, palatines, parasphenoid, and vomer; (c)
surrounding Meckel's' cartilage and forming the lower jaw: angulare, supra-angulare, operculare, and dentale. (See Figs. 243, 244
and 245.)
 
The embryonic bird's skull is characterized by a wealth of
distinct bones that is absolutely reptilian; but in the course of
development these fuse together so completely that it is only in
the facial and visceral regions that the sutures can be distinguished
readily.
 
In order of development the membrane bones precede the
cartilage bones, though the latter are phylogenetically the older.
Thus, about the end of the ninth day, the following bones are
present in the form of delicate reticulated bars and plates: all
four bones of the mandible, the faint outline of the premaxillae,
the central part of the maxillae, the jugal and quadratojugal, the
nasals, the palatines and pterygoids. The base of the squamosal
is also indicated by a small triangular plate ending superiorly in
branching trabeculae, delicate as frost-work. A faint band of
perichondral bone is beginning to appear around the otic process
of the quadrate, the first of the cartilage bones to show any
trace of ossification. These ossifications appear practically
simultaneously as shown by the examination of the earlier stages.
 
On the twelfth day these areas have expanded considerably,
and the frontals and prefrontals (lachrymals) are formed; the
rostrum of the parasphenoid is also laid down, and the exoccipitals appear in the cartilage at the sides of the foramen magnum.
The parietals appear behind the squamosal (Fig. 242) about the
thirteenth day; the basioccipitals soon after. The supraoc
 
 
434 THE DEVELOPMENT OF THE CHICK
 
cipital appears as a pair of ossifications in the tectum synoticum
on each side of the dorsal middle line, subsequently fusing
together.
 
A detailed history of the mode of ossification of all the various
bones of the skull would be out of place in this book. The figures
illustrate some points not described in the text. The reader is
referred to W. K. Parker (1869) and to Gaupp (1905).
 
V. Appendicular Skeleton
 
The appendicular skeleton includes the skeleton of the limbs
and of the girdles that unite the limbs to the axial skeleton. The
fore and hind-limbs, being essentially homonymous structures,
exhibit many resemblances in their development.
 
The Fore-limb. The pectoral girdle and skeleton of the
wing develop from the mesenchyme that occupies the axis and
base of the w^ng-bud, as it exists on the fourth day of incubation. It is probably of sclerotomic origin, but it is not known
exactly how many somites are concerned in the chick, nor which
ones. After the wing has gained considerable length (fifth day)
it can be seen from the innervation that three somites are principally involved in the wing proper, viz., the fourteenth, fifteenth,
and sixteenth of the trunk. But it is probable that the mesenchyme of the base of the wing-bud, from which the pectoral
girdle is formed, is derived from a larger number of somites.
 
It is important, then, to note first of all that the scapula,
coracoid, clavicle, humerus, and distal skeletal elements of the
wing are represented on the fourth day by a single condensation
of mesenchyme, which corresponds essentially to the glenoid
region of the definitive skeleton. From this common mass a
projection grows out distally in the axis of the wing-bud, and
three projections proximally in different directions in the bodywall. These projections are (1) the primordium of the wingskeleton, (2) of the scapula, (3) of the coracoid, (4) of the
clavicle.
 
The Pectoral Girdle. The elements of the pectoral girdle are
thus outgrowths of a common mass of mesenchyme. The scapula
process grows backward dorsal to the ribs; the coracoid process
grows ventralward and slightly posterior towards the primordium
of the sternum, thus forming an angle slightly less than a right
angle with the scapular process; and the clavicular process grows
 
 
 
THE SKELETON 435
 
out in front of the coracoid process ventrally and towards the
middle hne. ThevSe processes are quite well developed on the
fifth day, and increase considerably in length on the sixth day,
when the hind end of the scapula nearly reaches the anterior end
of the ilium, and the lower end of the coracoid is very close to
the sternum. The elements are still continuous in the glenoid
region.
 
About the end of the sixth day independent centers of chondrification appear in the scapula and coracoid respectively near
their imion; these spread distally and fuse centrally, so that
on the seventh day the coraco-scapula is a single bent cartilaginous element. In the angle of the bend, however (the future
coraco-scapular joint), the cartilage is in a less advanced condition than in the bodies of the two elements. The clavicular
process, on the other hand, never shows any trace of cartilage
formation, either in early or more advanced stages, but ossifies
directly from the membrane. It separates from the other elements of the pectoral girdle, though not completel}', on the eighth
dav.
 
The scapula and coracoid ossify in a perichondral fashion,
beginning on the twelfth da}^, from independent centers, which
approach but never fuse, leaving a permanent cartilaginous
connection (Fig. 242). The clavicle, on the other hand, is a
purely membrane bone; bony deposit begins in the axis of the
membranous rods on the eighth or ninth days, soon forming
fretted rods that approach in the mid-ventral line by enlarged
ends, which fuse directly without the intervention of any median
element about the twelfth to thirteenth day, thus forming the
furcula or wish-bone (Fig. 246).
 
The nature of the clavicle in birds has been the subject of a sharp
difference of opinion. On the one hand, it has been maintained that it
is double in its origin, consisting of a cartilaginous axis (procoracoid)
on which a true membrane bone is secondarily grafted (Gegenbaur, Fiirbringer, Parker, and others) ; on the other hand, all cartilaginous preformation in its origin has been denied by Rathke, Goette, and Kulczycki. After
careful examination of series of sections in all critical stages, and of
preparations made by the potash method, I feel certain that in the chick
at least there is no cartilaginous preformation. It is still possible (indeed probable on the basis of comparative anatomy) that the theory
of its double origin is correct phylogenetically; but it is certain that the
 
 
 
436
 
 
 
THE DEVELOPMENT OF THE CHICK
 
 
 
procoracoid component does not develop beyond the membranous stage
in the chick. It is interesting that the clavicle is the first center of ossification in the body, though perichondral ossification of some of the
long bones begins almost as soon.
 
The Wing-bones. The primordium of the wing-bones is
found in the axial mesenchyme of the wing-bud, which is originally continuous with the primordium of the pectoral girdle, and
shows no trace of the future elements of the skeleton. The
differentiation of the elements accompanies in general the external
differentiation of the wing illustrated in Figs. 121 to 124, Chapter
VII. The humerus, radius, and ulna arise by membranous differentiation in the mesenchyme in substantially their definitive
relations; they pass through a complete cartilaginous stage and
 
 
 
 
Fig. 246. — Photograph of the pectoral
girdle of a chick embryo of 274 hours;
prepared by the potash method. (Preparation and photograph by Roy L.
Moodie.)
 
1, Coracoid. 2, Clavicle. 3, Scapula.
4, Humerus.
 
 
 
then ossify in a perichondral fashion (see Fig. 242). In the
carpus, metacarpus, and phalanges, more elements are formed
in the membrane and cartilage than persist in the adult. Elimination as well as fusion takes place. These parts will therefore
require separate description.
 
As birds have descended from pentadactyl ancestors with
subsequent reduction of carpus, metacarpus, and phalanges, it
is naturally of considerable interest to learn how much of the
ancestral history is preserved in the embryology. The hand is
represented in the embryo of six days by the spatulate extremity
of the fore-limb, which includes the elements of carpus, metacarpus, and phalanges. From this expansion five digital rays
grow out simultaneously, the first and fifth being relatively
 
 
 
THE SKELETOX
 
 
 
437
 
 
 
small; the second, third, and fourth represent the persistent digits.
In each ray is a membranous skeletal element, which, however,
soon disappears in the first and fifth. Thus there are distinct
indications of a i^entadactyl stage in the development of the
bird's wing.
 
In the definitive skeleton there are but two carpal bones,
viz., a radiale at the extremity of the radius, and an ulnare at
the extremity of the ulna. In the embryo there is evidence of
seven transitory pieces in the carpus arranged in two rows, proximal and distal (Fig. 247). In the proximal row only two car
 
 
M.c.J
 
M c. 2
 
 
 
^A*"?^
 
 
 
jPcA
 
 
 
 
-U
 
 
 
M'c.-?^
 
 
 
Cp.^ Cp3 ^•^■
 
 
 
P'c/).
 
 
 
Fig. 247. — Skeleton of the wing of a chick embryo of 8 days. (After W.
 
K. Parker.)
 
Cp. 2, 3, and 4, Second, third, and fourth carpalia. C. U., Centraloiilnare. H., Humerus. I. R., Intermedio-radiale. M'c. 2, 3, 4, Second,
third, and fourth metacarpalia. P'ch., Perichondral bone R., Radius.
U., Ulna.
 
tilages appear, viz., the radiale and ulnare; but in earlier stages
each appears to be derived from two centers: the radiale from a
radiale s.s. and an intermedium, the ulnare from an ulnare s.s.
and a centrale. Evidence of such double origin of each is found
also in the cartilaginous condition {v. Parker, 1888). Four
elements in all enter into the composition of this proximal row.
In the distal row there are three distinct elements corresponding
to the three persistent digits, and representing, therefore, carpalia
II, III, and IV. These subsequently fuse with one another,
and with the heads of the metacarpals to produce the carpometacarpus.
 
On the seventh day the metacarpus is represented Ijy three
cartilages corresponding to the three persistent digits, viz., II,
 
 
 
438 THE DEVELOPMENT OF THE CHICK
 
III, IV. Metacarpal II is only about one third the length of III.
Metacarpal IV is much more slender than III, and is bowed out
in the middle, meeting III at both ends. The elements are at
first distinct, but II and III fuse at their proximal ends in the
process of ossification. Cartilaginous rudiments of metacarpals
I and V have also been found by Parker, Rosenberg, and Leighton.
As to the phalanges, Parker finds two cartilages in II, three
in III, and two in IV on the seventh day; but already on the
eighth day the distal phalanges of III and I^' have fused with
the next proximal one.
 
As regards the homology of the digits of the wing, the author has
adopted the views of Owen, Mehnert, Norsa, and Leighton, that they
represent numbers II, III, and IV, which seem to be better supported
by the embryological evidence than the view of ^Meckel, Gegenbauer,
Parker, and others, that they represent I, II, and HI.
 
The Skeleton of the Hind-limb. The skeleton of the hindlimb and pelvic girdle develops from a continuous mass of mesenchyme situated at the base of the leg-bud. The original center
of the mass represents the acetabular region; it grows out in four
processes: (1) a lateral projection in the axis of the leg-bud, the
primordium of the leg-skeleton proper, (2) a dorsal process, the
primordium of the ilium; and two diverging ventral processes,
one in front of the acetabulum (3) the pubis, and one behind
(4) the ischium. In the membranous condition the elements are
continuous. The definitive elements develop either as separate
cartilao-e centers in the common mass (usually), or as separate
centers of ossification in a common cartilaginous mass (ilium
 
and ischium).
 
The Pelvic Girdle. The primitive relations of the elements of
the pelvic girdle in Larus ridibundus is shown in Fig. 248, which
represents a section in the sagittal plane of the body, and thus
does not necessarily show the full extent of any of the cartilaginous elements, but only their general relations. The head of the
femur is seen in the acetabulum, the broad plate of the ilium
above and the pubis and ischium as cartilaginous rods of almost
equal width below, the pubis in front and the ischiimi behind
the acetabuhmi. In this stage the pehdc girdle, in this and
many other species of birds, consists of three separate elements
on each side in essentially reptilian relations.
 
 
 
THE SKELETOX
 
 
 
439
 
 
 
In the chick at a corresponding age the ihum is much more
extensive, and the ischium is united with it by cartilage- the
pubis, however, has only a membranous connection with the
ilium (contra Johnson). In the course of development the distal
ends of the ischium and pubis rotate backwards until the two
elements come to lie substantially parallel to the ilium (Figs.
242 and 249). The displacement of the ischium and pubis may
 
 
 
//.
 
 
 
u^
 
 
 
'^lx'~^^'~^i''
 
 
/s.n.
 
 
 
Is.
 
 
 
Cr.N.
 
 
 
oi.JV.
 
 
 
Fig. 248. — Sagittal section of the right half of the body
of Lams ridibundus, to show the composition of the pelvic girdle; x 35. Length of the leg-bud of the embryo,
0.4 mm. (After Mehnert.)
F., Femur, cr. N., Crural nerve. II., Ihum. I. s., Ischium. Is. N., Ischial nerve, ob. N., Obturator nerve.
P., Pubis.
 
be associated wdth the upright gait of birds; it is fully established
on the eighth day in the chick. The mode of ossification, which
is perichondral, is shown in Fig. 249.
 
Later, the ilium obtains a very extensive pre- and postacetabular union with the vertebrae. I have fomid no evidence
in a complete series of preparations (potash) of attachment by
ribs arising as indei^endent ossifications. The ischium also fuses
 
 
 
440
 
 
 
THE DEVELOPMENT OF THE CHICK
 
 
 
with the ventral posterior border of the iUum, and the pubis,
 
except at its anterior and posterior ends, with the free border
 
of the ischium.
 
The spina iliaca, a pre-acetabular, bony process of the ihum,
 
requires special mention inasmuch as it has been interpreted (by Marsh) as the
true pubis of birds, and the
element ordinarily named
the pubis as homologous to
the post-pubis of some reptiles. There is no evidence
for this in the development.
The spina iliaca develops as
a cartilaginous outgrowth of
the ilium and ossifies from
the latter, not from an independent center (Mehnert).
 
The Leg-skeleton. The
skeleton of the leg develops
from the axial mesenchyme,
which is at first continuous
with the primordium of the
pelvic girdle. In the process
of chondrification it segments into a larger number
of elements than found in
the adult, some of which are
suppressed and others fuse
together. The digits grow
out from the palate-like expansion of the primitive
limb in the same fashion as
in the wing. In general the
 
separate elements arise in the proximo-distal order (Figs. 242 and
 
249)..
 
The femur requires no special description; ossification begins
 
on the ninth day.
 
The primordium of the fibula is from the first more slender
than that of the tibia, though relatively far larger than the adult
 
 
 
 
Fig. 249. — Photograph of the skeleton
 
of the leg of a chick embryo of 15 days'
 
incubation. Prepared by the potash
 
method. (Preparation and photograph
 
by Roy L. Moodie.)
 
1, Tibia. 2, Fibula. 3, Patella. 4,
Femur. 5, Ilium. 6, Pleurocentra of
sacral vertebrae. 7, Ischium. 8, Pubis.
9, Tarsal ossification. 10, Second, third,
and fourth metatarsals. 11, First metatarsal. I, II, III, IV, First, second, third,
and fourth digits.
 
 
 
THE SKELETON
 
 
 
441
 
 
 
fibula. The fibular cartilage extends the entire length of the crus,
but ossification is confined largely to its proximal end; on the
fourteenth day its lower half is represented by a thread-like filament of bone. '
 
No separate tarsal elements are found in the adult; but in the
embryo there are at least three cartilages,
viz., a fibulare, tibiale and a large distal
element opposite the three main metatarsals. In the course of development, the
two proximal elements fuse with one
another, and with the distal end of the
tibia. The distal element fuses with
the three main metatarsals, first with the
second, then with the fourth, and lastly
with the third (Johnson).
 
Five digits are formed in the membranous stage of the skeleton. In the
case of the fifth chgit, only a small nodule
of cartilage (fifth metatarsal) develops and
soon disappears. The second, third, and
fourth are the chief digits; the first is
relatively small. ^Metatarsals 2, 3, and 4
are long and ossify separately in a perichondral fashion. They become applied
near their middle and fuse with one
another and with the distal tarsal element
to form the tarso-metatarsus of the adult
(Fig. 250). The first metatarsal is short,
lying on the preaxial side of the distal end
of the others (Fig. 249); it ossifies after
the first phalanx. The number of phalanges is 2, 3, 4, and 5 in the first, second, third, and fourth digits
respectively (Fig. 249).
 
The patella is clearly seen in potash preparations of thirteen-day
chicks. At the same time there is a distinct, though iiiiiuite, separate
center of ossification in the tarsal region (Fig. 249).
 
 
 
 
Fig. 250. — Photograph
of the skeleton of the
foot of a chick embryo
of 15 days' incubation.
(Preparation and photograph by Roy L.
Moodie)
 
1, 2, 3, 4, First, second,
third, and fourth digits.
M 2, M 3, M 4, Second,
third, and fourth metatarsals.
 
 
 
APPENDIX
 
 
 
GENERAL LITERATURE
 
V. Baer, C. E., L'eber Entwickelurigsgeschichte der Tiere. Beobachtung
 
und Reflexion. Konigsbcrg, 1828 u. 1837.
 
id., 2. Teil — Herausgegeben von Stieda. Konigsberg, 1888.
Duval, Mathias, Atlas d'embryologie. (With 40 plates.) Paris, 1889.
Foster, M., and Balfour, F. M., The Elements of Embryology. Second
 
Edition revised. London, 1883.
Gadow, Hans, Die Vogel, Bronn's Klassen und Ordniingen des Thier-Reichs,
 
Bd. VI, Abth. 4, 1898.
Handbuch der vergleichenden und experimentellen Entwickelimgslehre der
 
Wirbeltiere. Edited by Dr. Oskar Hertwig and written by numerous
 
collaborators. Jena, 1901-1907.
Hls, W., LTntersuchungen fiber die erste Anlage des Wirbeltierleibes. Die
 
erste Entwickelung des Hiihnchens im Ei. Leipzig, 1868.
Keibel, F., and Abraham, K., Normaltafeln zur Entwickelungsgeschichte
 
des Huhnes (Gallus domesticus). Jena, 1900.
V. KoLLiKER, A., Entwickelungsgeschichte des Menschen und der hoheren
 
Thiere. Zweite Aufl. Leipzig, 1879.
Marshall, A. M., Vertebrate Embryology. A Text-book for Students and
 
Practitioners. (Ch. IV, The Development of the Chick.) New York
 
and London, 1893.
MiNOT, C. S., Laboratory Text-book of Embryology. Philadelphia, 1903.
Pander, Beitrage zur Entwickelungsgeschichte des Hiihnchens im Ei. Wiirz
burg, 1817.
Prevost et Dumas, Memoire sur le developpement du poulet dans I'oeuf.
 
Ann. Sc. Nat., Vol. XII, 1827.
Preyer, W., Specielle Physiologic des Embryo. Leipzig, 1885.
Remak, R., Untersuchungen iiber die Entwickelung der Wirbelthiere. Berlin, 1855.
 
LITERATURE — CHAPTER I
 
Bartelmez, George W., 1912, The Bilaterality of the Pigeon's Egg. A
Study in Egg Organization from the First Growth Period of the Oocyte
to the Beginning of Cleavage. Journ. of Morph. Vol. 23., pp. 269-328.
 
CoSTE, M., Histoire generale et particuliere du developpement des corps
organises, T. I. (Formation of Egg in Oviduct, see Chap. VI). Paris,
1847-1849.
 
D 'Hollander, F., Recherches sur I'oogenese et sur la structure et la signification du noyau vitellin de Balbiani chez les oiseaux. Archiv. d'anat.
micr., T. VII, 1905.
 
Gegenbaur, C, Ueber den Bau und die Entwickelung der Wirbeltiereier
mit partieller Dottertheilung. Archiv. Anat. u. Phys., 1861.
 
443
 
 
 
444 APPENDIX
 
Glaser, Otto, 1913, On the Origin of Double-yolked Eggs. Biol. Bull.,
 
Vol. 24, pp. 175-186.
HoLL, M., Ueber die Reifung der Eizelle des Huhnes. Sitzungsber. Akad
Wiss. Wien, math.-nat. KL, Bd. XCIX, Abth. Ill, 1890.
 
V. Nathusius, W., Zur Bildung der Eihiillen. Zool. Anz. Bd. XIX, 1896.
 
Die Entwickelung von Schale und Schalenhaut des Hiihnereies im
 
Ovidukt. Zeitschr. wiss. Zool., Bd. LV, 1893.
 
Parker, G. H., Double Hen's Eggs. American Naturalist, Vol. XL. 1906.
 
Pearl, Raymond and Curtis, M. R, 1912, Studies on the Physiology of
 
Reproduction in the Domestic Fowl. V. Data Regarding the Physiology
 
of the Oviduct. Journ. of Exp. Zoology. Vol. 12, pp. 99-132.
Riddle, Oscar, 1911, On the Formation, Significance and Chemistry of
 
the White and Yellow Yolk of Ova. Journ. of Morph., Vol. 22, pp.
 
455-490.
SoNNENBRODT, 1908, Die Wachstunsperiode der Oocyte des Huhns. Arch.
 
f. mikr. Anat. w. Entw. Bd. 72, pp. 415-480.
Waldeyer, W., Die Geschlechtszellen. Handbuch der vergl. und exper.
 
Entwickelungslehre der \Yirbeltiere. Bd. I, T. 1, 1901.
 
LITERATURE — CHAPTER II
 
Andrews, E. A., Some Intercellular Connections in an Egg of a Fowl. The
Johns Hopkins University Circular. Notes from the Biological Laboratory, March, 1907.
 
Barfurth, D., Versuche iiber die parthenogenetische Furchung des Hiihnereies. Arch. Entw.-mech., Bd. 2, 1895.
 
Blount, Mary, The Early Development of the Pigeon's Egg with Especial
Reference to the Supernumerary Sperm-nuclei, the Periblast and the
Germ-wall. Biol. Bull., Vol. XIII, 1907.
 
Duval, M., De la formation du l^lastoderm dans Foeuf d'oiseau. Ann. Sc.
Nat. Zool., Ser. 6, T. XVIII, 1884.
 
Gasser, E., Der Parablast und der Keimwall der Vogelkeimscheibe. Sitzungsber. der Ges. zur Beford. d. ges. Naturwiss. zu Marburg, 1883.
Eierstocksei und Eileiterei des Vogels. Ibid, 1884.
 
Gotte, a., Beitrage zur Entwickelungsgeschichte der Wirbeltiere, II. Die
Bildung der Keimblatter und des Blutes im Hiihnerei. Archiv. mikr.
Anat., Bd. X, 1874.
 
Harper, E. H., The Fertilization and Early Development of the Pigeon's
Egg. Am. Jour. Anat., Vol. Ill, 1904.
 
KiONKA, H., Die Furchung des Hiihnereies. Anat. Hefte, Bd. Ill, 1894.
 
Lau, H., Die parthenogenetische Furchung des Hiihnereies. Inaug. Dissert.
Jurjew — Dorpat., 1894.
 
Oellacher, J., Untersuchungen iiber die Furchung und Blatterl)ildung im
Hiihnerei. Studien iiber experimentelle Pathologic von Strieker, Bd
 
I, 1869.
Oellacher, J., Die Veranderungen des unbefruchteten Keimes des Huhnereies
im Eileiter und bei Bebriitungsversuchen. Zeitschr. wiss. Zool., Bd.
XXII, 1872.
 
 
 
APPENDIX 445
 
Patterson, J. Thomas, Gastrulation in the Pigeon's Egg; a ^Morphological
 
and Experimental Study. The Journ. of Morph., Vol. 29, pp. 65-123,
 
1909.
Patterson, J. Thomas, Studies on the Early Dev^elopment of the Hen's
 
Egg. 1. History of the Early Cleavage and of the Accessory Cleavage.
 
The Journ. of Morph., Vol. 21, pp. 101-134, 1910.
Rauber, a., Ueber die Stellung des Hiihnchens im Entwicklungsplan.
 
Leipzig, 1876.
Sobotta, J., Die Reifung und Befruchtung des Wirbeltiereies. Ergeb.
 
Anat. u. Entwickelungsgesch., Bd. V, 1895.
 
LITERATURE — CHAPTER III
 
Edwards, C. L., The Physiological Zero and the Index of Development for
 
the Egg of the Domestic Fowl, Gallus Domesticus. Am. Journ. Physiol.,
 
Vol. VI, 1902.
Eycleshymer, a. C, Some Observations and Experiments on the Natural
 
and Artificial Incubation of the Egg of the Common Fowl. Biol. Bull.,
 
Vol. XII, 1907.
Fere, Cm., Note sur I'influence de la temperature sur I'incubation de I'oeuf
 
de poule. Journ. de I'anatomie et de la physiologic, Paris, T. XXX,
 
1894.
 
LITERATURE — CHAPTERS IV AND V
 
Assheton, R., An Experimental Examination into the Growth of the Blastoderm of the Chick. Proc. Roy. Soc, London, Vol. LX, 1896.
 
Balfour, F. M. The Development and Growth of the Layers of the Blastoderm. Quar. Jour. Micr. Sc, Vol. XIII, 1873.
 
On the Disappearance of the Primitive Groove in the Embryo Chick.
lUd.
 
Balfour, F. M., and Deighton, A Renewed Study of the Germinal Layers
of the Chick. Quar. Jour. Micr. Sc, Vol. XXII, 1882.
 
DissE, J., Die Entwickelung des mittleren Keimblattes im Hiihnerei. Arch,
mikr. Anat., Bd. XV, 1878.
 
DuRSY, Emil, Der Primitivstreif des Hiihnchens. Lahr, 1866.
 
Duval, Mathias, Etudes sur la hgne primitive de rembr3'on du poulet.
Ann. Sc. Nat. Zool., Ser. 6, T. VII, 1S7S.
 
De la formation du blastoderm dans I'oiuf d'oiseau. Ann. Sc. Nat.
Zool., Ser. 6, T. XVIII. Paris, 1884.
 
Evans, Herbert M. On the Development of the Aorta), Cardinal and
UmbiUcal Veins and other Blood-vessels of Vertebrate Embryos from
Capillaries. Anatomical Record., Vol. 3, pp. 498-518, 1909.
 
Fol, H., Recherches sur le developpement des protovertcbres chez I'embryon
du poulet. Arch. sc. phys. et nat. Geneve, T. II, 1884.
 
Gasser, Lieber den Primitivstreifen bei Vogelembryonen. Sitz.-Ber. d. Gcs.
z. Beforcl. d. ges. Naturw. z. Marburg, 1877.
 
Der Primitivestreif bei Vogelembryonen (Huhn w. Gans). Schriften
d. Ges. z. Beford. d. ges. Naturw. z. Marburg, Bd. XI, Suppl. Heft 1,
1879.
 
 
 
446 APPENDIX
 
Gasser, Beitrage zur Kenntnis der Vogelkeimscheibe. Arch. Anat. u
 
Entw., 1882.
 
Der Parablast unci der Keimwall der Vogelkeimscheibe. Sitz.-Ber.
 
d. Ges. z. Beford. d. ges. Naturw. z. Marburg, 1883.
GoETTE, A., Beitrage zur Entwickelungsgeschichte der Wirbeltiere. II.
 
Die Bildung der Keimblatter und des Blutes im Hiihnerei. Arch. mikr.
 
Anat., Bd. X, 1874.
Hertwig, O., Die Lehre von den Keimblattern. Handbuch der vergl. und
 
exper. Entwickehuigslehre der Wirbeltiere. Vol. I. Jena, 1903.
His, W., Der Keimwall des Htihnereies und die Entstehung der para
blastischen Zellen. Arch. Anat. und Entw., Bd. I, 1876.
 
Neue Untersuchung liber die Bildung des Hiihnerembryo. Arch.
 
Anat. und Entw., 1877.
 
Lecithoblast und Angioblast der "Wirbelthiere. Histogenetische
 
Studien. Abh. der math.-phys. Klasse der Konigl. Sachs. Ges. der
 
Wissenschaften, Bd. XXVI. Leipzig, 1900.
 
Die Bildung der Somatopleura und der Gefasse beim Hiihnchen.
 
Anat. Anz., Bd. XXI, 1902.
Hubbard, M. E., Some Experiments on the Order of Succession of the
 
Somites of the Chick. Am. Nat., Vol. 42, pp. 466-471, 1908.
Janosik, J., Beitrag zur Kenntnis des Keimwulstes bei Vogeln. Sitz-Ber
Akad. Wiss. Wien, math.-phys. KL, Bd. LXXXIV, 1882.
Roller, C, Beitrage zur Kenntnis des Hiihnerkeimes im Beginne der Be
briitung. Sitzungsber. Wien. Akad. Wiss., math.-nat. KL, 1879.
Untersuchungen liber die Blatterbildung im Hlihnerkeim. Arch.
 
mikr. Anat., Bd. XX, 1881.
V. Kolliker, a., Zur Entwickelung der Keimblatter im Hiihnerei. Verb.
 
phys.-med. Ges. Wlirzburg, Bd. VIII, 1875.
KopscH,FR.,Ueber die Bedeutung des Primitivstreifens beim Hiihnerembryo,
 
und liber die ihm homologen Theile bei den Embryonen der niederen
 
Wirbeltiere. Intern. Monatschr. f. Anat. u. Phys., Bd. XIX, 1902.
MiTROPHANOW, P. J., Teratogene Studien. II. Experimentellen Beo
bachtungen liber die erste Anlage der Primitivrinne der Vogel. Arch.
 
Entw.-mech., Bd. VI, 1898.
 
Beobachtungen liber die erste Entwickelung der Vogel. Anat.
 
Hefte, Bd. XII, 1899.
Now^\cK, K., Neue Untersuchungen liber die Bildung der beiden primiiren
 
Keimblatter und die Entstehung des Primitivstreifen beim Hiihnerembryo. Inaug. Diss. Berlin, 1902.
Patterson, J. Thos., The Order of Appearance of the Anterior Somites in
 
the Chick. Biol. Bull., Vol. XIII, 1907.
Patterson, J. T. An experimental Study on the Development of the Vascular
 
Area of the Chick Blastoderm. Biol. Bull. XVI, pp. 83-90, 1909.
Peebles, Florence. Some Experiments on the Primitive Streak of the
 
Chick. Arch. Entw.-mech., Bd. VII, 1898.
 
A Prehminary Note on the Position of the Primitive Streak and its
 
Relation to the Embryo of the Chick. Biol. Bull., Vol. IV, 1903.
 
 
 
APPENDIX 447
 
Peebles, Florence, The Location of the Chick Embryo upon the Blastoderm. Journ. Exp. Zool., Vol. I, 1904.
Platt, J. B., Studies on the Primitive Axial Segmentation of the Chick.
 
Bull. Mus. Comp. Zool. Harv., Vol. 17, 1889.
Rabl, C, Theorie des Mesoderms. Morph. Jahrb., Bde. XV und XIX,
 
1889 and 1892.
Rauber, a., Primitivstreifen und Neurula der Wirbelthiere, in normaler
 
und pathologischer Beziehung. Leipzig, 1877.
 
Ueber die embryonale Anlage des Hiihnchens. Centralb. d. med.
 
Wiss., Bd. XII, 1875.
 
Ueber die erste Entwickelung der Vogel und die Bedeutung der Primi
tivrinne. Sitz.-ber. d. naturf. Ges. zu Leipzig, 1876.
Rex, Hugo, Ueber das Mesoderm des Vorderkopfes der Ente. Archiv.
 
■ mikr. Anat., Bd. L., 1897.
RiiCKERT, J., Entwickelung der extra-embryonalen Gefasse der Vogel. Hand
buch der vergl. w. exp. Entw.-lehre der Wirbelthiere, Bd. I, T. 1,
 
1906.
 
Ueber die Abstammung der bluthaltigen Gefassanlagen beim Huhn,
 
und uber die Entstehung des Randsinus beim Huhn und bei Torpedo.
 
Sitzungsber. der Bay. Akad. Wiss., 1903.
ScHAUiNSLAND, H., Bcitrage zur Biologie und Entwickelung der Hatteria
 
nebst Bemerkungen uber die Entwickelung der Sauropsiden. Anat.
 
Anz. XV, 1899.
ViALLETOX, Developpement des aortes chez I'embryon de poulet. Journ.
 
de I'^nat. T. XXVIII, 1892. See also Anat. Anz., Bd. VII, 1892.
ViRCHOW, H., Der Dottersack des Huhns. Internat. Beitrage zur wiss.
 
Med., Bd. I, 1891.
Waldeyer, W., Bemerkungen uber die Keimblatter und den Primitivstreifen
 
bei der Entwickelung des Huhnerembryo. Zeitschr. rationeller Medicin,
 
1869.
Whitman, C. O., A Rare Form of the Blastoderm of the Chick and its Bearing
 
on the Question of the Formation of the Vertebrate Embryo. Quar.
 
Journ. Micr. Sc, Vol. XXIII, 1883.
WiLLL\MS, Leonard W. The Somites of the Chick. Am. Journ. of Anat.,
 
Vol. 11, pp. 5.5-100, 1910.
 
Literature to Chapter VI included in following chapters.
 
LITERATURE — CHAPTER VII
 
CHARBONNEiy-SALLE ct Phisalix, De I'evolution postembryonnaire du
 
sac vitellin chez les oiseaux. C. R. Acad. Sc, Paris, 1886.
Dareste, C, Sur I'absence totale de I'amnios dans les embryons de poule.
 
C. R. Acad. Sc, Paris, T. LXXXVIII, 1879.
Duval, M., Etudes histologiques et morphologiques sur les annexes des
 
embryons d'oiseau. Journ. de I'anat, et de la phys., T. XX, 1884.
Etude sur I'origine de Tallantoide chez le poulet. Rev. sc. nat.,
 
Paris, 1877.
 
 
 
448 APPENDIX
 
Duval, M., Sur ime organe placentoide chez rembryon des oiseaux. C. R.
 
Acad. Sc, Paris, 1884.
Fromann, C, Ueber die Struktur der Dotterhaut des Huhnes. Sitz.-ber.
 
Jen. Ges. Medizin u. Naturw., 1879.
FuLLEBORN, F., Beitrage zur Entwickelung der Allantois der Vogel. Diss.,
 
Berlin, 1894.
Gasser, E., Beitrage zur Entwickelungsgeschichte der Allantois, der Miiller
schen Gange iind des Afters. Frankfurt a. M., 1874.
GoTTE, A., Beitrage zur Entwickelungsgeschichte des Darmkanals im Hiihn
chen. Tubingen, 1867.
HiROTA, S., On the Sero-amniotic Connection and the Foetal Membranes in
 
the Chick. Journ. Coll. Sc. Imp. Univ. Japan, Vol. VI, Part IV, 1^94.
LiLLiE, Frank R., Experimental Studies on the Development of the Organs
 
in the Embryo of the Fowl (Gallus domesticus): 1. Experiments on the
 
Amnion and the Production of Anamniote Embryos of the Chick. Biol.
 
Bull., Vol. V, 1903. 2. The Development of Defective Embryos and
 
the Power of Regeneration. Biol. Bull., Vol. VII, 1904.
Mertens, H., Beitrage zur Kenntniss der Fotushiillen im Vogelei. Meckels
 
Archiv, 1830.
Mitrophanow, p. J., Note sur la structure et la formation de I'enveloppe
 
du jaune de I'ceuf de la poule. Bibliogr. Anat., Paris, 1898.
PopoFF, Demetrius, Die Dottersackgefasse des Huhnes. Wiesbaden, 1894.
Pott, R., and Preyer, W., Ueber denGaswechsel und die chemischen Verander
ungen des Hiihnereies wahrend der Bebriitung. Archiv. ges. Phys., 1882.
Preyer, W., Specielle Physiologic des Embryo. Leipzig, 1885.
Ravn, E., Ueber die mesodermfreie Stelle in der Keimscheibe des Huhner
embryo. Arch. Anat. u. Entw., 1886.
 
Ueber den Allantoisstiel des Hiihnerembryo. Verh. Anat. Ges., 1898.
ScHAUiNSLAND, H., Die Entwickelung der Eihaute der Reptilien und der
 
Vogel. Handbuch der vergl. und exp. Entw.-lehre der Wirbeltiere. Bd.
 
I, T. 2, 1902.
 
Beitrage zur Entwickelungsgeschichte der Wirbeltiere. II. Beitrage zur
 
Entwickelungsgeschichte der Eihaute der Sauropsiden. Bibliotheca
 
Zoologica, 1903.
Schenk, S. L., Beitrage zur Lehre vom Amnion. Archiv. mikr. Anat., Bd.
 
VII, 1871.
 
Ueber die Aufnahme des Nahrungsdotters wahrend des Embryonal
lebens. Sitz.-ber. Akad. Wiss. Wien, math.-nat. Kl., 1897.
Shore, T. W., and Pickering, J. W., The Proamnion and Amnion in the
 
Chick. Journ. of Anat. and Phys., Vol. XXIV, 1889.
Soboleff, Die Verletzung des Amnions wahrend der Bebriitung. Mittheil,
 
embryolog. Inst., Wien, 1883.
Strahl, H., Eihaute und Placenta der Sauropsiden. Ergeb. Anat. u. Entw.
gesch., Bd. I, 1891.
Stuart, T. P. A., A Mode of Demonstrating the Developing Membranes in
 
the Chick. Journ. Anat. and Phys., London, Vol. XXV, 1899.
ViRCHOW, H., Beobachtungen am Hiihnerei; iiber das dritte Keimblatt
 
im Bereiche des Dottersackes. Virchow's Arch., Bd. LXII, 1874.
 
 
 
APPENDIX 449
 
ViRCHOW, H., Ueber das Epithel des Dottersackes im Hiihnerei. Diss., Berlin.
1875.
 
Der Dottersack des Huhnes. Internat. Beitrage zur wissenschaft.
Medizin, Bd. I, 1891.
 
Das Dotterorgan der Wirbeltiere. Zeitschr. wiss. Zool., Bd. LIII,
Suppl., 1892.
 
Das Dotterorgan der Wirbelthiere. Arch. mikr. Anat., Bd. XL, 1892.
Dottersyncytium, Keimhautrand und Beziehungen zur Koncrescenzlehre. Ergeb. Anat. u. Entw., Bd. VI, 1897.
 
Ueber Entwickelungsvorgange, welche sich in den letzten Bruttagen
am Hiihnerei abspielen. Anat. Anz., Bd. IV, BerHn, 1889.
VuLPiAX, La physiologie de I'amnios et de I'allantoide chez les oiseaux.
 
Mem. soc. biol., Paris, 1858.
Weldox, W. F. R., Prof, de Vries on the Origin of Species. (Includes experiments on amnion.) Biometrica, Vol. I, 1902.
 
LITERATURE — CHAPTER VIII
 
Beard, J., Morphological Studies, II. The Development of the Peripheral
 
Nervous System of Vertebrates. Pt. I. Elasmobranchs and Aves.
 
Quar. Journ. Micr. Sc, Vol. XXIX, 1888.
Beraneck, E., Etudes sur les replis medullaires du poulet. Recueil Zool.
 
Suisse, Vol. IV, 1887.
Bethe, Albrecht, Allgemeine Anatomic und Physiologie des Nervensys
tems. Leipzig, 1903.
Brandis, F., Untersuchungen iiber das Gehirn der Vogel. Arch. mikr.
 
Anat., Bd. XLI, 1893; Bd. XLIII, 1894; Bd. XLIV, 1895.
Burrows, Montrose T., The Growth of Tissues of the Chick Embryo
 
Outside the Animal Body, with Special Reference to the Nervous System.
 
Journ. Exp. Zoology, Vol. 10, pp. 63-83, 1911.
Cajal, S. R. y., Sur I'origine et les ramifications des fibres nerveuses de la
 
moelle embryonnaire. Anat. Anz., Bd. V, 1890.
 
A quelle epoque aparaissent les expansions des cellules nerveuses de
 
la moelle epiniere du poulet. Anat. Anz., Bd. V, 1890.
Froriep, a., Ueber Anlagen von Sinnesorganen am Facialis, Glossopha
ryngeus und Vagus, iiber die genetische Stellung des Vagus zum Hypo
glossus, und iiber die Herkunft der Zungenmuskulatur. Arch. Anat.
 
u. Entw., 1885.
Carpenter, Frederick Walton, The Development of the Oculomotor Nerve,
 
the Ciliary Ganglion, and the Abducent Nerve in the Chick. Bull.
 
Mus. Comp. Zool. Harv. Vol. XLVIII, 1906.
DissE, J., Die erste Entwickelung des Riechnerven. Anat. Hefte, Abth. I,
 
Bd. IX, 1897.
GoLoviNE, E., Sur le developpement du systeme ganglionnaire chez le poulet.
 
Anat. Anz., Bd. V, 1890.
GoRONOwiTscH, N., Die axiale und die laterale (A. Goette) Kopfmetamerie
 
der Vogeleml^ryonen. Anat. Anz., Bd. VII, 1892.
 
L'ntersuchungen iiber die Entwickelung der Sogenannten " Ganglien
leisten " im Kopfe der Vogelembryonen. Morph. Jahrb., Bd. XX, 1893.
 
 
 
450 APPENDIX
 
Heinrich, Georg, Untersuchungen iiber die Anlage des Grosshirns beim
Hiihnchen. Sitz.-ber. d. Ges. f. Morph. u. Phys. in Munchen, Bd. XII,
 
1897.
Hill, Charles, Developmental History of the Primary Segments of the
 
Vertebrate Head. Zool. Jahrbucher, Abth. Anat. Bd. XIII, 1900.
His, W., Die Neuroblasten und deren Entstehung im embryonalen Mark.
 
Abh. math.-physik. Klasse, Konigl. Sachs. Ges. Wiss., Bd. XV, 1889.
Histogenese und Zusammenhang der Nervenelemente. Arch. Anat.
u. Entw., Suppl., 1890.
Ueber das frontale Ende des Gehirnrohres. Arch. Anat. u. Entw., 1893.
Ueber das frontale Ende und iiber die natiirliche Eintheilung des
Gehirnrohres. Verh. anat. Ges., Bd. VII, 1893.
His, W. (Jr.)» Ueber die Entwickelung des Bauchsympathicus beim Hiihnchen und Menschen. Arch. Anat. u. Entw., Suppl., 1897.
V. KoLLiKER, Ueber die erste Entwickelung der Nervi olfactorii. Sitz.-ber.
 
phys. med. Ges. zu Wiirzburg, 1890.
V. KuPFFER, K., Die Morphogenie des Centralnervensystems. Handbuch der
 
vergl. und exp. Entwickelungslehre der Wirbeltiere, Kap. VIII, IP, 1905.
Lewis, M. R. and Lewis, W. H., The Cultivation of Tissues from Chick
 
Embroyos in Solutions of NaCl, CaCl2, KCl and NaHCOg. Anatomical
 
Record, Vol. 5, pp. 277-293. See also Anat. Rec, Vol. 6, nos. 1 and 5, 1911.
Marshall, A. M., The Development of the Cranial Nerves in the Chick.
 
Quar. Journ. Micr. Sc, Vol. XVIII, 1878.
 
The Segmental Value of the Cranial Nerves. Journ. Anat. and Physiol.,
 
Vol. XVI, 1882.
v. MiHALCOVics, v., Entwickelungsgeschichte des Gehirns. Leipzig, 1877.
Onodi, a. D., Ueber die Entwickelung des sympathischen Nervensy stems.
 
Arch. mikr. Anat., Bd. XXVI, 1886.
Rabl, C, Ueber die IMetamerie des Wirbelthierkopfes. Verh. anat. Ges.,
 
VI, 1892.
RuBASCHKiN, W., Ueber die Beziehungen des Nervus trigeminus zur Riech
schleimhaut. Anat. Anz., Bd. XXII, 1903.
Weber, A., Contribution a Tetude de la metamerism du cerveau anterieur
 
chez quelques oiseaux. Arch, d'anat. microsc, Paris, T. Ill, 1900.
Van Wijhe, J. W., L^eber Somiten und Nerven im Kopfe von Vogel- und
 
Reptilien-embryonen. Zool. Anz. Bd. IX, 1886.
 
Ueber die Kopfsegmente und das Geruchsorgan der Wirbelthiere
 
Zool. Anz., Bd. IX, 1886.
 
LITERATURE — CHAPTER IX
Organs of Special Sense
 
A. The Eye
 
Addario, C, Sulla struttura del vitreo embryonale e de' neonati, sulla matrice del vitreo e suU' origine della zonula. Ann. OttalmoL, Anno 30,
1901-1902.
 
 
 
APPENDIX 451
 
AddariOjC, Ueber die Matrix desGlaskorpers im menschlichen und thierischen
 
Auge. Vorlauf. Mitth. Anat. Anz., Bd. XXI, 19(32.
Agababow, Untersuchiingen iiber die Natur der Zonula ciliaris. Arch.
 
mikr. Anat., Bd. L, 1897.
Angelucci, a., Ueber Entwiekelung und Bau des vorderen Uvealtractus der
 
Vertebraten. Arch. mikr. Anat., Bd. XIX, 1881.
Arnold, J., Beitrage zur Entwickekmgsgeschichte des Auges. Heidelberg,
 
1874.
AssHETON, R., On the Development of the Optic Nerve of Vertebrates, and
 
the Choroidal Fissure of Embryonic Life. Quar. Journ. Micr. Sc, Vol.
 
XXXIV, 1892.
Bernd, Adolph Hugo, Die Entwiekelung des Pecten im Auge des Hiihn
chens aus den Blattern der Augenblase. Bonn, 1905.
Cajal, S. R. y., Sur la morphologie et les connexions des elements de la retine
 
des oiseaux. Anat. Anz. Bd. IV, 1889.
 
Sur la fine structure du lobe optique des oiseaux et sur I'origine reelle
 
des nerfs optiques. Int. Monatschr. Anat. u. Phys., Bd. VIII, 1891.
Cirincione, G., Ueber die Entwiekelung der Capsula perilenticularis. Arch.
 
Anat. u. Entw., Suppl. Bd., Jahrg. 1897.
 
Zur Entwiekelung des Wirbeltierauges. Ueber die Entwiekelung
 
des Capsula perilenticularis. Leipzig, 1898.
 
Ueber die Genese des Glaskorpers bei Wirbelthieren. Verh. Anat.
 
Ges., 17. Versamml. in Heidelberg, 1903.
Collin, R., Recherches sur le developpement du muscle sphincter de I'iris
 
chez les oiseaux. Bibliog. Anat., T. XII, fasc. V. Paris, 1903.
Froriep, a., Ueber die Entwiekelung des Sehnerven. Anat. Anz., Bd. VI,
 
1891.
 
Die Entwiekelung des Auges der Wirbeltiere. Handb. der vergl. u.
 
exp. Entw.-l. der Wirbeltiere, Bd. II, 1905.
HuscHKE, E., Lieber die erste Entwiekelung des Auges und die damit zusam
menhangende Cyklopie. Meckel's Arch., 1832.
Kessler, L., Untersuchungen liber die Entwiekelung des Auges, angestellt
 
am Hiihnchen und Tauben. Dissertation. Dorpat, 1871.
 
Die Entwiekelung des Auges der Wirbelthiere. Leipzig, 1877.
V. Kolliker, a., LTeber die Entwiekelung und Bedeutung des Glaskorpers.
 
Verh. anat. Ges., 17. Vers. Heidelberg, 1903.
 
Die Entwiekelung und Bedeutung des Glaskorpers. Zeitschr. wiss.
 
Zool., Bd. LXXVII, 1904.
V. Lenhossek, M., Die Entwiekelung des Glaskorpers. Leipzig, 1903.
Lewis, W. H., Wandering Pigmented Cells Arising from the Epithelium of
 
the Optic Cup, with Observations on the Origin of the M. Sphincter
 
Pupillffi in the Chick. Am. Journ. Anat., Vol. II, 1903.
LocY, W. A., Contribution to the Structure and Development of the Vertebrate Head. Journ. Morph., Vol. XI. Boston, 1895.
 
Accessory Optic Vesicles in the Chick Embryo. Anat. Anz., Bd. XIV,
 
1897.
NussBAUM, M., Zur Riickbildung embryonaler Anlagen. (Corneal papillae
 
of chick embryos.) Archiv. mikr. Anat., Bd. LVII, 1901.
 
 
 
452 APPENDIX
 
NussBAUM, M., Die Pars ciliaris retinae des Vogelauges. Arch. mikr. Anat., Bd.
 
LVII, 1901.
 
Die Entwiekelung der Binnenmuskeln des Aiiges der Wirbeltiere.
 
Arch. mikr. Anat., Bd. LVIII, 1901.
Rabl, C, Ziir Frage nach der Entwickehmg des Glaskorpers. Anat. Anz.,
 
Bd. XXII, 1903.
 
Ueber den Ban und die Entwickehmg der Linse. II. Reptihen imd
 
Vogel. Zeitschr. wiss. Zool., Bd. LXV, 1899.
Robinson, A., On the Formation and Structure of the Optic Nerve, and its
 
Relation to the Optic Stalk. Journ. Anat. and Phys. London, 1896.
SziLi, A.V. Beitrag zur Kenntniss der Anatomic und Entwickelungsgeschichte
 
der hinteren Irisschichten, etc. Arch. Opthalm., Bd. LIII, 1902.
 
Zur Anatomic und Entwickelungsgeschichte der hinteren Irisschichten, etc. Anat. Anz., Bd. XX, 1901.
 
Zur Glaskorperfrage. Anat. Anz. Bd. XXIV, 1904.
ToRNATOLA, Origiuc et nature du corps vitre. Rev. gener. d 'opthalm. Annee
 
14, 1897.
UcKE, A., Epithelreste am Opticus und auf der Retina. Arch. mikr. Anat.,
 
Bd. XXXVIII, 1891.
 
Zur Entw^ickelung des Pigmentepithels der Retina. Diss, aus Dorpat.
 
Petersburg, 1 89 1 .
ViRCHOW, H., Facher, Zapfen, Leiste, Polster, Gefasse im Glaskorperraum
 
von Wirbelthieren, sowie damit in Verbindung stehenden Fragen. Er
gebn. Anat. u. Entw., Bd. X. Berlin, 1900.
Weysse, a. W., and Burgess, W. S., Histogenesis of the Retina. Am.
 
Naturalist, Vol. XL, 1906.
 
 
 
B. The Nose
 
Born, G., Die Nasenhohlen und der Thranennasengang der amnioten Wir
belthiere II. Morph. Jahrb., Bd. V, 1879; Bd. VIII, 1883.
CoHN, Franz, Zur Entwickelungsgeschichte des Geruchsorgans des Hiihn
chens. Arch. mikr. Anat., Bd. LXI, 1903.
Dieulafe, Leon, Les fosses nasales des vertebres (morphologic et embry
ologie). Journ. de I'anat. et de la phys., T. 40 and 41, 1904 and 1905.
 
(Translated by Hanau W. Loeb: Ann. of Otol., Rhin. and Laryng., Mar.,
 
June and Sept., 1900.)
Disse, J., Die erste Entwiekelung des Riechnerven. Anat. Hefte, Bd. IX,
 
1897.
Ganin, M., Einige Thatsachen zur Frage iiber das Jacobsohn'sche Organ der
 
Vogel. Arb. d. naturf. Ges. Charkoff, 1890 (russisch). Abstr. Zool.
 
Anz., 1890.
V. KoLLiKER, A., Ueber die Entwickehmg der Geruchsorgane beim Menschen
 
und Hiihnchen. Wiirzburger med. Zeitschr., Bd. I, 1860.
V. MiHALKOvics, v., Nasenhohle und Jacobson'sche Organ. Anat. Hefte,
 
I. Abth., Bd. XI, 1898.
Peter, Karl, Entwickehmg des Geruchsorgans und Jakobson'sche Organs
 
in der Reihe der Wirbeltiere. Bildung der ausseren Nase und des
 
 
 
APPENDIX 453
 
Gaumens. Handbuch der vergl, und experiment. Entwickelimgslehre
 
der Wirbeltiere. IP, 1902.
Preobraschensky, L., Beitrage zur Lehre liber die Entwiekelung des Ge
ruchsorganes des Huhnes. Mitth. embryol. Inst. Wien, 1892.
PuTELLi, F., Ueber das Verhalten der Zellen der Riechschleimhaut bei
 
Hiihnerembryonen friiher Stadien. Mitth. embr. Inst. Wien, 1889.
 
C. The Ear
 
Hasse, C, Beitrage zur Entwiekelung der Gewebe der hautigen Vogel
schnecke. Zeitschr. wiss. Zool., Bd. XVII, 1867.
HuscHKE, Ueber die erste Bildungsgeschichte des Auges und Ohres beim
 
bebriiteten Hiihnchen. Isis von Oken, 1831.
Kastschenko, N., Das Schlundspaltengebiet des Hiihnchens. Arch. Anat.
 
u. Entw., 1887.
Keibel, Ueber die erste Bildung des Labyrinthanhanges. Anat. Anz., Bd.
 
XVI, 1899.
Krause, R., Die Entwickekmg des Aquaeductus Vestibuh, s. Ductus endo
lymphaticus. Anat. Anz., Bd. XIX, 1901.  


Die Entwickekmgsgeschichte des hautigen Bogenganges. Arch. mikr.
===Literature — Chapter X===


Anat., Bd. XXXV, 1890.
MoLDENHAUER, W., Die Entwickcking des mittleren und des ausseren Ohres.
Morph. Jahrb., Bd. Ill, 1877.
PoLi, C, Sviluppo della vesicula auditiva; studio morphologico. Genoa,
1896.
Zur Entwickekmg der Gehorblase bei den WirbeUieren. Arch. mikr.
Anat., Bd. XLVIII, 1897.
Retzius, G., Das Gehororgan der Wirbelthiere. II. Theil, Reptihen Vogel,
Sanger. Stockhokn. 1881-1884.
RoTHiG, p., und Brugsch, Theodor, Die Entwickekmg des Labyrintkes
beim Huhn. Archiv. mikr. Anat., Bd. LIX, 1902.
RtJDiNGER, Zur Entwickekmg des hautigen Bogenganges des inneren Ohres.
Sitzungsber. Akad. Miinchen, 1888.
LITERATURE — CHAPTER X
The Alimentary Tract and Its Appendages  
The Alimentary Tract and Its Appendages  


Line 6,489: Line 816:
embrologiche. Monit. zook Itak, Anno 1, 1890.  
embrologiche. Monit. zook Itak, Anno 1, 1890.  


454 APPENDIX


GoppERT, E., Die Bedeutimg der Zunge ftir den secundaren Gaumen und den  
GoppERT, E., Die Bedeutimg der Zunge ftir den secundaren Gaumen und den  

Latest revision as of 10:57, 22 November 2020

Review - Lillie’s Development of the Chicken - an Introduction to Embryology 3rd Edn. (1952)  
Lillie’s Development of the Chicken Introduction to Embryology. 3rd Edition, revised by Howarp L. Hamilton. (Pp. 574; 283 figs.; 14 plates; $8.50.) New York: H. Holt & Co. 1952.


The writing of the present edition was begun in 1945 at the request of Dr Frank R. Lillie himself with Dr B. H. Willier acting as advisory editor. It was Dr Lillie’s hope that he might live to see the new edition in print but this was not to be. The general outline of previous editions has been preserved. Part 1, which consists of six chapters, is devoted to an account of the early embryology up to and including the 3rd day. The account of the development of the embryo is given on a general basis and in addition a detailed account is given of specially selected stages.


Part 2 of the book consists of nine chapters and is an account of the development of the embryo from the 4th day to hatching; the various systems and external form are described as separate entities. A few chapters, such as the one dealing with the external form of the embryo and the embryonic membranes, and the one describing the body cavities, mesenteries and septum transversum, have remained relatively unchanged. Chapter 4, ‘From laying to the formation of the first somite’, chapter 8; ‘The nervous system’, and chapter 13, ‘The urogenital system’, are more or less completely rewritten. A new chapter, the fifteenth, describing the development of the integument, has been added. The other chapters have been extensively revised.


The new accounts are based on recent literature, but the author has tried to follow Dr Lillie’s example of going to the chick itself to check questionable points. To this end some original work is included in the text, but it is to be regretted that the author has not indicated more clearly which parts of the text result from this original work. The only clear indications consist of an opinion on the processes concerned with the formation of endoderm (p. 101) and two footnotes, one dealing with the coelomic cavity (p. 149) and one with the tail bud (p. 176). A further footnote refers to a communication from Rawles on the patency of the ductus arteriosus in the newly-hatched chick (p. 462).


This book is very well written and its format is attractive. The book reaches a happy compromise which makes it a most readable introduction to embryology while yet remaining an invaluable reference work for the research worker.


There is little to criticize in this work which has evidently been prepared with great care, but future editions might be improved by a rearrangement of the bibliography. The references should be listed at the end of the chapter they concern and not in an appendix of 32 pages at the end of the book. Also the magnification of drawings and photographs of early embryos should be given. Figs. 153 and 155 would be improved by being photographs rather than drawings of sagittal sections through an embryo. In fig. 222 the drawings are too small and too faint.


Apart from these minor faults the present work is a credit to the author and had Dr Lillie lived he would have been proud to have his name associated with it. It will continue to perpetuate Dr Lillie’s influence on the development of embryology.

W. J. Hamilton

chicken

Review - Lillie’s Development of the Chicken - an Introduction to Embryology 3rd Edn. (1952)  
Lillie’s Development of the Chicken Introduction to Embryology. 3rd Edition, revised by Howarp L. Hamilton. (Pp. 574; 283 figs.; 14 plates; $8.50.) New York: H. Holt & Co. 1952.

The writing of the present edition was begun in 1945 at the request of Dr Frank R. Lillie himself with Dr B. H. Willier acting as advisory editor. It was Dr Lillie’s hope that he might live to see the new edition in print but this was not to be. The general outline of previous editions has been preserved. Part 1, which consists of six chapters, is devoted to an account of the early embryology up to and including the 3rd day. The account of the development of the embryo is given on a general basis and in addition a detailed account is given of specially selected stages.

Part 2 of the book consists of nine chapters and is an account of the development of the embryo from the 4th day to hatching; the various systems and external form are described as separate entities. A few chapters, such as the one dealing with the external form of the embryo and the embryonic membranes, and the one describing the body cavities, mesenteries and septum transversum, have remained relatively unchanged. Chapter 4, ‘From laying to the formation of the first somite’, chapter 8; ‘The nervous system’, and chapter 13, ‘The urogenital system’, are more or less completely rewritten. A new chapter, the fifteenth, describing the development of the integument, has been added. The other chapters have been extensively revised.

The new accounts are based on recent literature, but the author has tried to follow Dr Lillie’s example of going to the chick itself to check questionable points. To this end some original work is included in the text, but it is to be regretted that the author has not indicated more clearly which parts of the text result from this original work. The only clear indications consist of an opinion on the processes concerned with the formation of endoderm (p. 101) and two footnotes, one dealing with the coelomic cavity (p. 149) and one with the tail bud (p. 176). A further footnote refers to a communication from Rawles on the patency of the ductus arteriosus in the newly-hatched chick (p. 462).

This book is very well written and its format is attractive. The book reaches a happy compromise which makes it a most readable introduction to embryology while yet remaining an invaluable reference work for the research worker.

There is little to criticize in this work which has evidently been prepared with great care, but future editions might be improved by a rearrangement of the bibliography. The references should be listed at the end of the chapter they concern and not in an appendix of 32 pages at the end of the book. Also the magnification of drawings and photographs of early embryos should be given. Figs. 153 and 155 would be improved by being photographs rather than drawings of sagittal sections through an embryo. In fig. 222 the drawings are too small and too faint.

Apart from these minor faults the present work is a credit to the author and had Dr Lillie lived he would have been proud to have his name associated with it. It will continue to perpetuate Dr Lillie’s influence on the development of embryology.

W. J. Hamilton

chicken

THE DEVELOPMENT OF THE CHICK - AN INTRODUCTION TO EMBRYOLOGY

BY

FRANK R. LILLIE

PROFESSOR IN THE UNIVERSITY OP CHICAGO

SECOND EDITION, REVISED

NEW YORK HENRY HOLT AND COMPANY

1919

Copyright, 1908, 1919,

BY

HENRY HOLT AND COMPANY


Part I The Early Development To The End Of The Third Day

Appendix

General Literature

V. Baer, C. E., L'eber Entwickelurigsgeschichte der Tiere. Beobachtung

und Reflexion. Konigsbcrg, 1828 u. 1837.

id., 2. Teil — Herausgegeben von Stieda. Konigsberg, 1888. Duval, Mathias, Atlas d'embryologie. (With 40 plates.) Paris, 1889. Foster, M., and Balfour, F. M., The Elements of Embryology. Second Edition revised. London, 1883. Gadow, Hans, Die Vogel, Bronn's Klassen und Ordniingen des Thier-Reichs, Bd. VI, Abth. 4, 1898. Handbuch der vergleichenden und experimentellen Entwickelimgslehre der Wirbeltiere. Edited by Dr. Oskar Hertwig and written by numerous collaborators. Jena, 1901-1907.


Hls, W., LTntersuchungen fiber die erste Anlage des Wirbeltierleibes. Die erste Entwickelung des Hiihnchens im Ei. Leipzig, 1868. Keibel, F., and Abraham, K., Normaltafeln zur Entwickelungsgeschichte des Huhnes (Gallus domesticus). Jena, 1900.


V. KoLLiKER, A., Entwickelungsgeschichte des Menschen und der hoheren

Thiere. Zweite Aufl. Leipzig, 1879. Marshall, A. M., Vertebrate Embryology. A Text-book for Students and

Practitioners. (Ch. IV, The Development of the Chick.) New York

and London, 1893. MiNOT, C. S., Laboratory Text-book of Embryology. Philadelphia, 1903. Pander, Beitrage zur Entwickelungsgeschichte des Hiihnchens im Ei. Wiirz burg, 1817. Prevost et Dumas, Memoire sur le developpement du poulet dans I'oeuf.

Ann. Sc. Nat., Vol. XII, 1827. Preyer, W., Specielle Physiologic des Embryo. Leipzig, 1885. Remak, R., Untersuchungen iiber die Entwickelung der Wirbelthiere. Berlin, 1855.

Literature — Chapter I

Bartelmez, George W., 1912, The Bilaterality of the Pigeon's Egg. A Study in Egg Organization from the First Growth Period of the Oocyte to the Beginning of Cleavage. Journ. of Morph. Vol. 23., pp. 269-328.

CoSTE, M., Histoire generale et particuliere du developpement des corps organises, T. I. (Formation of Egg in Oviduct, see Chap. VI). Paris, 1847-1849.

D 'Hollander, F., Recherches sur I'oogenese et sur la structure et la signification du noyau vitellin de Balbiani chez les oiseaux. Archiv. d'anat. micr., T. VII, 1905.

Gegenbaur, C, Ueber den Bau und die Entwickelung der Wirbeltiereier mit partieller Dottertheilung. Archiv. Anat. u. Phys., 1861.


Glaser, Otto, 1913, On the Origin of Double-yolked Eggs. Biol. Bull.,

Vol. 24, pp. 175-186. HoLL, M., Ueber die Reifung der Eizelle des Huhnes. Sitzungsber. Akad Wiss. Wien, math.-nat. KL, Bd. XCIX, Abth. Ill, 1890.

V. Nathusius, W., Zur Bildung der Eihiillen. Zool. Anz. Bd. XIX, 1896.

Die Entwickelung von Schale und Schalenhaut des Hiihnereies im

Ovidukt. Zeitschr. wiss. Zool., Bd. LV, 1893.

Parker, G. H., Double Hen's Eggs. American Naturalist, Vol. XL. 1906.

Pearl, Raymond and Curtis, M. R, 1912, Studies on the Physiology of

Reproduction in the Domestic Fowl. V. Data Regarding the Physiology

of the Oviduct. Journ. of Exp. Zoology. Vol. 12, pp. 99-132. Riddle, Oscar, 1911, On the Formation, Significance and Chemistry of the White and Yellow Yolk of Ova. Journ. of Morph., Vol. 22, pp. 455-490.

SoNNENBRODT, 1908, Die Wachstunsperiode der Oocyte des Huhns. Arch.

f. mikr. Anat. w. Entw. Bd. 72, pp. 415-480. Waldeyer, W., Die Geschlechtszellen. Handbuch der vergl. und exper.

Entwickelungslehre der \Yirbeltiere. Bd. I, T. 1, 1901.

Literature — Chapter II

Andrews, E. A., Some Intercellular Connections in an Egg of a Fowl. The Johns Hopkins University Circular. Notes from the Biological Laboratory, March, 1907.

Barfurth, D., Versuche iiber die parthenogenetische Furchung des Hiihnereies. Arch. Entw.-mech., Bd. 2, 1895.

Blount, Mary, The Early Development of the Pigeon's Egg with Especial Reference to the Supernumerary Sperm-nuclei, the Periblast and the Germ-wall. Biol. Bull., Vol. XIII, 1907.

Duval, M., De la formation du l^lastoderm dans Foeuf d'oiseau. Ann. Sc. Nat. Zool., Ser. 6, T. XVIII, 1884.

Gasser, E., Der Parablast und der Keimwall der Vogelkeimscheibe. Sitzungsber. der Ges. zur Beford. d. ges. Naturwiss. zu Marburg, 1883. Eierstocksei und Eileiterei des Vogels. Ibid, 1884.

Gotte, a., Beitrage zur Entwickelungsgeschichte der Wirbeltiere, II. Die Bildung der Keimblatter und des Blutes im Hiihnerei. Archiv. mikr. Anat., Bd. X, 1874.

Harper, E. H., The Fertilization and Early Development of the Pigeon's Egg. Am. Jour. Anat., Vol. Ill, 1904.

KiONKA, H., Die Furchung des Hiihnereies. Anat. Hefte, Bd. Ill, 1894.

Lau, H., Die parthenogenetische Furchung des Hiihnereies. Inaug. Dissert. Jurjew — Dorpat., 1894.

Oellacher, J., Untersuchungen iiber die Furchung und Blatterl)ildung im Hiihnerei. Studien iiber experimentelle Pathologic von Strieker, Bd

I, 1869. Oellacher, J., Die Veranderungen des unbefruchteten Keimes des Huhnereies im Eileiter und bei Bebriitungsversuchen. Zeitschr. wiss. Zool., Bd. XXII, 1872.


Patterson, J. Thomas, Gastrulation in the Pigeon's Egg; a ^Morphological

and Experimental Study. The Journ. of Morph., Vol. 29, pp. 65-123,

1909. Patterson, J. Thomas, Studies on the Early Dev^elopment of the Hen's

Egg. 1. History of the Early Cleavage and of the Accessory Cleavage.

The Journ. of Morph., Vol. 21, pp. 101-134, 1910. Rauber, a., Ueber die Stellung des Hiihnchens im Entwicklungsplan.

Leipzig, 1876. Sobotta, J., Die Reifung und Befruchtung des Wirbeltiereies. Ergeb.

Anat. u. Entwickelungsgesch., Bd. V, 1895.

Literature — Chapter III

Edwards, C. L., The Physiological Zero and the Index of Development for

the Egg of the Domestic Fowl, Gallus Domesticus. Am. Journ. Physiol.,

Vol. VI, 1902. Eycleshymer, a. C, Some Observations and Experiments on the Natural

and Artificial Incubation of the Egg of the Common Fowl. Biol. Bull.,

Vol. XII, 1907. Fere, Cm., Note sur I'influence de la temperature sur I'incubation de I'oeuf

de poule. Journ. de I'anatomie et de la physiologic, Paris, T. XXX,

1894.

Literature — Chapter IV and V

Assheton, R., An Experimental Examination into the Growth of the Blastoderm of the Chick. Proc. Roy. Soc, London, Vol. LX, 1896.

Balfour, F. M. The Development and Growth of the Layers of the Blastoderm. Quar. Jour. Micr. Sc, Vol. XIII, 1873.

On the Disappearance of the Primitive Groove in the Embryo Chick. lUd.

Balfour, F. M., and Deighton, A Renewed Study of the Germinal Layers of the Chick. Quar. Jour. Micr. Sc, Vol. XXII, 1882.

DissE, J., Die Entwickelung des mittleren Keimblattes im Hiihnerei. Arch, mikr. Anat., Bd. XV, 1878.

DuRSY, Emil, Der Primitivstreif des Hiihnchens. Lahr, 1866.

Duval, Mathias, Etudes sur la hgne primitive de rembr3'on du poulet. Ann. Sc. Nat. Zool., Ser. 6, T. VII, 1S7S.

De la formation du blastoderm dans I'oiuf d'oiseau. Ann. Sc. Nat. Zool., Ser. 6, T. XVIII. Paris, 1884.

Evans, Herbert M. On the Development of the Aorta), Cardinal and UmbiUcal Veins and other Blood-vessels of Vertebrate Embryos from Capillaries. Anatomical Record., Vol. 3, pp. 498-518, 1909.

Fol, H., Recherches sur le developpement des protovertcbres chez I'embryon du poulet. Arch. sc. phys. et nat. Geneve, T. II, 1884.

Gasser, Lieber den Primitivstreifen bei Vogelembryonen. Sitz.-Ber. d. Gcs. z. Beforcl. d. ges. Naturw. z. Marburg, 1877.

Der Primitivestreif bei Vogelembryonen (Huhn w. Gans). Schriften d. Ges. z. Beford. d. ges. Naturw. z. Marburg, Bd. XI, Suppl. Heft 1, 1879.


Gasser, Beitrage zur Kenntnis der Vogelkeimscheibe. Arch. Anat. u

Entw., 1882.

Der Parablast unci der Keimwall der Vogelkeimscheibe. Sitz.-Ber.

d. Ges. z. Beford. d. ges. Naturw. z. Marburg, 1883. GoETTE, A., Beitrage zur Entwickelungsgeschichte der Wirbeltiere. II.

Die Bildung der Keimblatter und des Blutes im Hiihnerei. Arch. mikr.

Anat., Bd. X, 1874. Hertwig, O., Die Lehre von den Keimblattern. Handbuch der vergl. und

exper. Entwickehuigslehre der Wirbeltiere. Vol. I. Jena, 1903. His, W., Der Keimwall des Htihnereies und die Entstehung der para blastischen Zellen. Arch. Anat. und Entw., Bd. I, 1876.

Neue Untersuchung liber die Bildung des Hiihnerembryo. Arch.

Anat. und Entw., 1877.

Lecithoblast und Angioblast der "Wirbelthiere. Histogenetische

Studien. Abh. der math.-phys. Klasse der Konigl. Sachs. Ges. der

Wissenschaften, Bd. XXVI. Leipzig, 1900.

Die Bildung der Somatopleura und der Gefasse beim Hiihnchen.

Anat. Anz., Bd. XXI, 1902. Hubbard, M. E., Some Experiments on the Order of Succession of the

Somites of the Chick. Am. Nat., Vol. 42, pp. 466-471, 1908. Janosik, J., Beitrag zur Kenntnis des Keimwulstes bei Vogeln. Sitz-Ber Akad. Wiss. Wien, math.-phys. KL, Bd. LXXXIV, 1882. Roller, C, Beitrage zur Kenntnis des Hiihnerkeimes im Beginne der Be briitung. Sitzungsber. Wien. Akad. Wiss., math.-nat. KL, 1879. Untersuchungen liber die Blatterbildung im Hlihnerkeim. Arch.

mikr. Anat., Bd. XX, 1881. V. Kolliker, a., Zur Entwickelung der Keimblatter im Hiihnerei. Verb.

phys.-med. Ges. Wlirzburg, Bd. VIII, 1875. KopscH,FR.,Ueber die Bedeutung des Primitivstreifens beim Hiihnerembryo,

und liber die ihm homologen Theile bei den Embryonen der niederen

Wirbeltiere. Intern. Monatschr. f. Anat. u. Phys., Bd. XIX, 1902. MiTROPHANOW, P. J., Teratogene Studien. II. Experimentellen Beo bachtungen liber die erste Anlage der Primitivrinne der Vogel. Arch.

Entw.-mech., Bd. VI, 1898.

Beobachtungen liber die erste Entwickelung der Vogel. Anat.

Hefte, Bd. XII, 1899. Now^\cK, K., Neue Untersuchungen liber die Bildung der beiden primiiren

Keimblatter und die Entstehung des Primitivstreifen beim Hiihnerembryo. Inaug. Diss. Berlin, 1902. Patterson, J. Thos., The Order of Appearance of the Anterior Somites in

the Chick. Biol. Bull., Vol. XIII, 1907. Patterson, J. T. An experimental Study on the Development of the Vascular

Area of the Chick Blastoderm. Biol. Bull. XVI, pp. 83-90, 1909. Peebles, Florence. Some Experiments on the Primitive Streak of the

Chick. Arch. Entw.-mech., Bd. VII, 1898.

A Prehminary Note on the Position of the Primitive Streak and its

Relation to the Embryo of the Chick. Biol. Bull., Vol. IV, 1903.


Peebles, Florence, The Location of the Chick Embryo upon the Blastoderm. Journ. Exp. Zool., Vol. I, 1904. Platt, J. B., Studies on the Primitive Axial Segmentation of the Chick.

Bull. Mus. Comp. Zool. Harv., Vol. 17, 1889. Rabl, C, Theorie des Mesoderms. Morph. Jahrb., Bde. XV und XIX,

1889 and 1892. Rauber, a., Primitivstreifen und Neurula der Wirbelthiere, in normaler

und pathologischer Beziehung. Leipzig, 1877.

Ueber die embryonale Anlage des Hiihnchens. Centralb. d. med.

Wiss., Bd. XII, 1875.

Ueber die erste Entwickelung der Vogel und die Bedeutung der Primi tivrinne. Sitz.-ber. d. naturf. Ges. zu Leipzig, 1876. Rex, Hugo, Ueber das Mesoderm des Vorderkopfes der Ente. Archiv. mikr. Anat., Bd. L., 1897.


RiiCKERT, J., Entwickelung der extra-embryonalen Gefasse der Vogel. Hand buch der vergl. w. exp. Entw.-lehre der Wirbelthiere, Bd. I, T. 1,

1906.

Ueber die Abstammung der bluthaltigen Gefassanlagen beim Huhn,

und uber die Entstehung des Randsinus beim Huhn und bei Torpedo.

Sitzungsber. der Bay. Akad. Wiss., 1903. ScHAUiNSLAND, H., Bcitrage zur Biologie und Entwickelung der Hatteria

nebst Bemerkungen uber die Entwickelung der Sauropsiden. Anat.

Anz. XV, 1899. ViALLETOX, Developpement des aortes chez I'embryon de poulet. Journ.

de I'^nat. T. XXVIII, 1892. See also Anat. Anz., Bd. VII, 1892. ViRCHOW, H., Der Dottersack des Huhns. Internat. Beitrage zur wiss.

Med., Bd. I, 1891. Waldeyer, W., Bemerkungen uber die Keimblatter und den Primitivstreifen

bei der Entwickelung des Huhnerembryo. Zeitschr. rationeller Medicin,

1869. Whitman, C. O., A Rare Form of the Blastoderm of the Chick and its Bearing

on the Question of the Formation of the Vertebrate Embryo. Quar.

Journ. Micr. Sc, Vol. XXIII, 1883. WiLLL\MS, Leonard W. The Somites of the Chick. Am. Journ. of Anat.,

Vol. 11, pp. 5.5-100, 1910.

Literature to Chapter VI included in following chapters.

Literature — Chapter VII

CHARBONNEiy-SALLE ct Phisalix, De I'evolution postembryonnaire du

sac vitellin chez les oiseaux. C. R. Acad. Sc, Paris, 1886. Dareste, C, Sur I'absence totale de I'amnios dans les embryons de poule.

C. R. Acad. Sc, Paris, T. LXXXVIII, 1879. Duval, M., Etudes histologiques et morphologiques sur les annexes des

embryons d'oiseau. Journ. de I'anat, et de la phys., T. XX, 1884. Etude sur I'origine de Tallantoide chez le poulet. Rev. sc. nat.,

Paris, 1877.


Duval, M., Sur ime organe placentoide chez rembryon des oiseaux. C. R.

Acad. Sc, Paris, 1884. Fromann, C, Ueber die Struktur der Dotterhaut des Huhnes. Sitz.-ber.

Jen. Ges. Medizin u. Naturw., 1879. FuLLEBORN, F., Beitrage zur Entwickelung der Allantois der Vogel. Diss.,

Berlin, 1894. Gasser, E., Beitrage zur Entwickelungsgeschichte der Allantois, der Miiller schen Gange iind des Afters. Frankfurt a. M., 1874. GoTTE, A., Beitrage zur Entwickelungsgeschichte des Darmkanals im Hiihn chen. Tubingen, 1867. HiROTA, S., On the Sero-amniotic Connection and the Foetal Membranes in

the Chick. Journ. Coll. Sc. Imp. Univ. Japan, Vol. VI, Part IV, 1^94. LiLLiE, Frank R., Experimental Studies on the Development of the Organs

in the Embryo of the Fowl (Gallus domesticus): 1. Experiments on the

Amnion and the Production of Anamniote Embryos of the Chick. Biol.

Bull., Vol. V, 1903. 2. The Development of Defective Embryos and

the Power of Regeneration. Biol. Bull., Vol. VII, 1904. Mertens, H., Beitrage zur Kenntniss der Fotushiillen im Vogelei. Meckels

Archiv, 1830. Mitrophanow, p. J., Note sur la structure et la formation de I'enveloppe

du jaune de I'ceuf de la poule. Bibliogr. Anat., Paris, 1898. PopoFF, Demetrius, Die Dottersackgefasse des Huhnes. Wiesbaden, 1894. Pott, R., and Preyer, W., Ueber denGaswechsel und die chemischen Verander ungen des Hiihnereies wahrend der Bebriitung. Archiv. ges. Phys., 1882. Preyer, W., Specielle Physiologic des Embryo. Leipzig, 1885. Ravn, E., Ueber die mesodermfreie Stelle in der Keimscheibe des Huhner embryo. Arch. Anat. u. Entw., 1886.

Ueber den Allantoisstiel des Hiihnerembryo. Verh. Anat. Ges., 1898. ScHAUiNSLAND, H., Die Entwickelung der Eihaute der Reptilien und der

Vogel. Handbuch der vergl. und exp. Entw.-lehre der Wirbeltiere. Bd.

I, T. 2, 1902.

Beitrage zur Entwickelungsgeschichte der Wirbeltiere. II. Beitrage zur

Entwickelungsgeschichte der Eihaute der Sauropsiden. Bibliotheca

Zoologica, 1903. Schenk, S. L., Beitrage zur Lehre vom Amnion. Archiv. mikr. Anat., Bd.

VII, 1871.

Ueber die Aufnahme des Nahrungsdotters wahrend des Embryonal lebens. Sitz.-ber. Akad. Wiss. Wien, math.-nat. Kl., 1897. Shore, T. W., and Pickering, J. W., The Proamnion and Amnion in the

Chick. Journ. of Anat. and Phys., Vol. XXIV, 1889. Soboleff, Die Verletzung des Amnions wahrend der Bebriitung. Mittheil,

embryolog. Inst., Wien, 1883. Strahl, H., Eihaute und Placenta der Sauropsiden. Ergeb. Anat. u. Entw. gesch., Bd. I, 1891. Stuart, T. P. A., A Mode of Demonstrating the Developing Membranes in

the Chick. Journ. Anat. and Phys., London, Vol. XXV, 1899. ViRCHOW, H., Beobachtungen am Hiihnerei; iiber das dritte Keimblatt

im Bereiche des Dottersackes. Virchow's Arch., Bd. LXII, 1874.


ViRCHOW, H., Ueber das Epithel des Dottersackes im Hiihnerei. Diss., Berlin. 1875.

Der Dottersack des Huhnes. Internat. Beitrage zur wissenschaft. Medizin, Bd. I, 1891.

Das Dotterorgan der Wirbeltiere. Zeitschr. wiss. Zool., Bd. LIII, Suppl., 1892.

Das Dotterorgan der Wirbelthiere. Arch. mikr. Anat., Bd. XL, 1892. Dottersyncytium, Keimhautrand und Beziehungen zur Koncrescenzlehre. Ergeb. Anat. u. Entw., Bd. VI, 1897.

Ueber Entwickelungsvorgange, welche sich in den letzten Bruttagen am Hiihnerei abspielen. Anat. Anz., Bd. IV, BerHn, 1889. VuLPiAX, La physiologie de I'amnios et de I'allantoide chez les oiseaux.

Mem. soc. biol., Paris, 1858. Weldox, W. F. R., Prof, de Vries on the Origin of Species. (Includes experiments on amnion.) Biometrica, Vol. I, 1902.

Literature — Chapter VIII

Beard, J., Morphological Studies, II. The Development of the Peripheral

Nervous System of Vertebrates. Pt. I. Elasmobranchs and Aves.

Quar. Journ. Micr. Sc, Vol. XXIX, 1888. Beraneck, E., Etudes sur les replis medullaires du poulet. Recueil Zool.

Suisse, Vol. IV, 1887. Bethe, Albrecht, Allgemeine Anatomic und Physiologie des Nervensys tems. Leipzig, 1903. Brandis, F., Untersuchungen iiber das Gehirn der Vogel. Arch. mikr.

Anat., Bd. XLI, 1893; Bd. XLIII, 1894; Bd. XLIV, 1895. Burrows, Montrose T., The Growth of Tissues of the Chick Embryo

Outside the Animal Body, with Special Reference to the Nervous System.

Journ. Exp. Zoology, Vol. 10, pp. 63-83, 1911. Cajal, S. R. y., Sur I'origine et les ramifications des fibres nerveuses de la

moelle embryonnaire. Anat. Anz., Bd. V, 1890.

A quelle epoque aparaissent les expansions des cellules nerveuses de

la moelle epiniere du poulet. Anat. Anz., Bd. V, 1890. Froriep, a., Ueber Anlagen von Sinnesorganen am Facialis, Glossopha ryngeus und Vagus, iiber die genetische Stellung des Vagus zum Hypo glossus, und iiber die Herkunft der Zungenmuskulatur. Arch. Anat.

u. Entw., 1885. Carpenter, Frederick Walton, The Development of the Oculomotor Nerve,

the Ciliary Ganglion, and the Abducent Nerve in the Chick. Bull.

Mus. Comp. Zool. Harv. Vol. XLVIII, 1906. DissE, J., Die erste Entwickelung des Riechnerven. Anat. Hefte, Abth. I,

Bd. IX, 1897. GoLoviNE, E., Sur le developpement du systeme ganglionnaire chez le poulet.

Anat. Anz., Bd. V, 1890. GoRONOwiTscH, N., Die axiale und die laterale (A. Goette) Kopfmetamerie

der Vogeleml^ryonen. Anat. Anz., Bd. VII, 1892.

L'ntersuchungen iiber die Entwickelung der Sogenannten " Ganglien leisten " im Kopfe der Vogelembryonen. Morph. Jahrb., Bd. XX, 1893.


Heinrich, Georg, Untersuchungen iiber die Anlage des Grosshirns beim Hiihnchen. Sitz.-ber. d. Ges. f. Morph. u. Phys. in Munchen, Bd. XII,

1897. Hill, Charles, Developmental History of the Primary Segments of the

Vertebrate Head. Zool. Jahrbucher, Abth. Anat. Bd. XIII, 1900. His, W., Die Neuroblasten und deren Entstehung im embryonalen Mark.

Abh. math.-physik. Klasse, Konigl. Sachs. Ges. Wiss., Bd. XV, 1889. Histogenese und Zusammenhang der Nervenelemente. Arch. Anat. u. Entw., Suppl., 1890. Ueber das frontale Ende des Gehirnrohres. Arch. Anat. u. Entw., 1893. Ueber das frontale Ende und iiber die natiirliche Eintheilung des Gehirnrohres. Verh. anat. Ges., Bd. VII, 1893. His, W. (Jr.)» Ueber die Entwickelung des Bauchsympathicus beim Hiihnchen und Menschen. Arch. Anat. u. Entw., Suppl., 1897. V. KoLLiKER, Ueber die erste Entwickelung der Nervi olfactorii. Sitz.-ber.

phys. med. Ges. zu Wiirzburg, 1890. V. KuPFFER, K., Die Morphogenie des Centralnervensystems. Handbuch der

vergl. und exp. Entwickelungslehre der Wirbeltiere, Kap. VIII, IP, 1905. Lewis, M. R. and Lewis, W. H., The Cultivation of Tissues from Chick

Embroyos in Solutions of NaCl, CaCl2, KCl and NaHCOg. Anatomical

Record, Vol. 5, pp. 277-293. See also Anat. Rec, Vol. 6, nos. 1 and 5, 1911. Marshall, A. M., The Development of the Cranial Nerves in the Chick.

Quar. Journ. Micr. Sc, Vol. XVIII, 1878.

The Segmental Value of the Cranial Nerves. Journ. Anat. and Physiol.,

Vol. XVI, 1882. v. MiHALCOVics, v., Entwickelungsgeschichte des Gehirns. Leipzig, 1877. Onodi, a. D., Ueber die Entwickelung des sympathischen Nervensy stems.

Arch. mikr. Anat., Bd. XXVI, 1886. Rabl, C, Ueber die IMetamerie des Wirbelthierkopfes. Verh. anat. Ges.,

VI, 1892. RuBASCHKiN, W., Ueber die Beziehungen des Nervus trigeminus zur Riech schleimhaut. Anat. Anz., Bd. XXII, 1903. Weber, A., Contribution a Tetude de la metamerism du cerveau anterieur

chez quelques oiseaux. Arch, d'anat. microsc, Paris, T. Ill, 1900. Van Wijhe, J. W., L^eber Somiten und Nerven im Kopfe von Vogel- und

Reptilien-embryonen. Zool. Anz. Bd. IX, 1886.

Ueber die Kopfsegmente und das Geruchsorgan der Wirbelthiere

Zool. Anz., Bd. IX, 1886.

Literature — Chapter IX

Organs of Special Sense

A. The Eye

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AddariOjC, Ueber die Matrix desGlaskorpers im menschlichen und thierischen

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mikr. Anat., Bd. L, 1897. Angelucci, a., Ueber Entwiekelung und Bau des vorderen Uvealtractus der

Vertebraten. Arch. mikr. Anat., Bd. XIX, 1881. Arnold, J., Beitrage zur Entwickekmgsgeschichte des Auges. Heidelberg,

1874. AssHETON, R., On the Development of the Optic Nerve of Vertebrates, and

the Choroidal Fissure of Embryonic Life. Quar. Journ. Micr. Sc, Vol.

XXXIV, 1892. Bernd, Adolph Hugo, Die Entwiekelung des Pecten im Auge des Hiihn chens aus den Blattern der Augenblase. Bonn, 1905. Cajal, S. R. y., Sur la morphologie et les connexions des elements de la retine

des oiseaux. Anat. Anz. Bd. IV, 1889.

Sur la fine structure du lobe optique des oiseaux et sur I'origine reelle

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Zur Entwiekelung des Wirbeltierauges. Ueber die Entwiekelung

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Ueber die Genese des Glaskorpers bei Wirbelthieren. Verh. Anat.

Ges., 17. Versamml. in Heidelberg, 1903. Collin, R., Recherches sur le developpement du muscle sphincter de I'iris

chez les oiseaux. Bibliog. Anat., T. XII, fasc. V. Paris, 1903. Froriep, a., Ueber die Entwiekelung des Sehnerven. Anat. Anz., Bd. VI,

1891.

Die Entwiekelung des Auges der Wirbeltiere. Handb. der vergl. u.

exp. Entw.-l. der Wirbeltiere, Bd. II, 1905. HuscHKE, E., Lieber die erste Entwiekelung des Auges und die damit zusam menhangende Cyklopie. Meckel's Arch., 1832. Kessler, L., Untersuchungen liber die Entwiekelung des Auges, angestellt

am Hiihnchen und Tauben. Dissertation. Dorpat, 1871.

Die Entwiekelung des Auges der Wirbelthiere. Leipzig, 1877. V. Kolliker, a., LTeber die Entwiekelung und Bedeutung des Glaskorpers.

Verh. anat. Ges., 17. Vers. Heidelberg, 1903.

Die Entwiekelung und Bedeutung des Glaskorpers. Zeitschr. wiss.

Zool., Bd. LXXVII, 1904. V. Lenhossek, M., Die Entwiekelung des Glaskorpers. Leipzig, 1903. Lewis, W. H., Wandering Pigmented Cells Arising from the Epithelium of

the Optic Cup, with Observations on the Origin of the M. Sphincter

Pupillffi in the Chick. Am. Journ. Anat., Vol. II, 1903. LocY, W. A., Contribution to the Structure and Development of the Vertebrate Head. Journ. Morph., Vol. XI. Boston, 1895.

Accessory Optic Vesicles in the Chick Embryo. Anat. Anz., Bd. XIV,

1897. NussBAUM, M., Zur Riickbildung embryonaler Anlagen. (Corneal papillae

of chick embryos.) Archiv. mikr. Anat., Bd. LVII, 1901.


NussBAUM, M., Die Pars ciliaris retinae des Vogelauges. Arch. mikr. Anat., Bd.

LVII, 1901.

Die Entwiekelung der Binnenmuskeln des Aiiges der Wirbeltiere.

Arch. mikr. Anat., Bd. LVIII, 1901. Rabl, C, Ziir Frage nach der Entwickehmg des Glaskorpers. Anat. Anz.,

Bd. XXII, 1903.

Ueber den Ban und die Entwickehmg der Linse. II. Reptihen imd

Vogel. Zeitschr. wiss. Zool., Bd. LXV, 1899. Robinson, A., On the Formation and Structure of the Optic Nerve, and its

Relation to the Optic Stalk. Journ. Anat. and Phys. London, 1896. SziLi, A.V. Beitrag zur Kenntniss der Anatomic und Entwickelungsgeschichte

der hinteren Irisschichten, etc. Arch. Opthalm., Bd. LIII, 1902.

Zur Anatomic und Entwickelungsgeschichte der hinteren Irisschichten, etc. Anat. Anz., Bd. XX, 1901.

Zur Glaskorperfrage. Anat. Anz. Bd. XXIV, 1904. ToRNATOLA, Origiuc et nature du corps vitre. Rev. gener. d 'opthalm. Annee

14, 1897. UcKE, A., Epithelreste am Opticus und auf der Retina. Arch. mikr. Anat.,

Bd. XXXVIII, 1891.

Zur Entw^ickelung des Pigmentepithels der Retina. Diss, aus Dorpat.

Petersburg, 1 89 1 . ViRCHOW, H., Facher, Zapfen, Leiste, Polster, Gefasse im Glaskorperraum

von Wirbelthieren, sowie damit in Verbindung stehenden Fragen. Er gebn. Anat. u. Entw., Bd. X. Berlin, 1900. Weysse, a. W., and Burgess, W. S., Histogenesis of the Retina. Am.

Naturalist, Vol. XL, 1906.


B. The Nose

Born, G., Die Nasenhohlen und der Thranennasengang der amnioten Wir belthiere II. Morph. Jahrb., Bd. V, 1879; Bd. VIII, 1883. CoHN, Franz, Zur Entwickelungsgeschichte des Geruchsorgans des Hiihn chens. Arch. mikr. Anat., Bd. LXI, 1903. Dieulafe, Leon, Les fosses nasales des vertebres (morphologic et embry ologie). Journ. de I'anat. et de la phys., T. 40 and 41, 1904 and 1905.

(Translated by Hanau W. Loeb: Ann. of Otol., Rhin. and Laryng., Mar.,

June and Sept., 1900.) Disse, J., Die erste Entwiekelung des Riechnerven. Anat. Hefte, Bd. IX,

1897. Ganin, M., Einige Thatsachen zur Frage iiber das Jacobsohn'sche Organ der

Vogel. Arb. d. naturf. Ges. Charkoff, 1890 (russisch). Abstr. Zool.

Anz., 1890. V. KoLLiKER, A., Ueber die Entwickehmg der Geruchsorgane beim Menschen

und Hiihnchen. Wiirzburger med. Zeitschr., Bd. I, 1860. V. MiHALKOvics, v., Nasenhohle und Jacobson'sche Organ. Anat. Hefte,

I. Abth., Bd. XI, 1898. Peter, Karl, Entwickehmg des Geruchsorgans und Jakobson'sche Organs

in der Reihe der Wirbeltiere. Bildung der ausseren Nase und des


Gaumens. Handbuch der vergl, und experiment. Entwickelimgslehre

der Wirbeltiere. IP, 1902. Preobraschensky, L., Beitrage zur Lehre liber die Entwiekelung des Ge ruchsorganes des Huhnes. Mitth. embryol. Inst. Wien, 1892. PuTELLi, F., Ueber das Verhalten der Zellen der Riechschleimhaut bei

Hiihnerembryonen friiher Stadien. Mitth. embr. Inst. Wien, 1889.

C. The Ear

Hasse, C, Beitrage zur Entwiekelung der Gewebe der hautigen Vogel schnecke. Zeitschr. wiss. Zool., Bd. XVII, 1867. HuscHKE, Ueber die erste Bildungsgeschichte des Auges und Ohres beim

bebriiteten Hiihnchen. Isis von Oken, 1831. Kastschenko, N., Das Schlundspaltengebiet des Hiihnchens. Arch. Anat.

u. Entw., 1887. Keibel, Ueber die erste Bildung des Labyrinthanhanges. Anat. Anz., Bd.

XVI, 1899. Krause, R., Die Entwickekmg des Aquaeductus Vestibuh, s. Ductus endo lymphaticus. Anat. Anz., Bd. XIX, 1901.

Die Entwickekmgsgeschichte des hautigen Bogenganges. Arch. mikr.

Anat., Bd. XXXV, 1890. MoLDENHAUER, W., Die Entwickcking des mittleren und des ausseren Ohres.

Morph. Jahrb., Bd. Ill, 1877. PoLi, C, Sviluppo della vesicula auditiva; studio morphologico. Genoa,

1896.

Zur Entwickekmg der Gehorblase bei den WirbeUieren. Arch. mikr.

Anat., Bd. XLVIII, 1897. Retzius, G., Das Gehororgan der Wirbelthiere. II. Theil, Reptihen Vogel,

Sanger. Stockhokn. 1881-1884. RoTHiG, p., und Brugsch, Theodor, Die Entwickekmg des Labyrintkes

beim Huhn. Archiv. mikr. Anat., Bd. LIX, 1902. RtJDiNGER, Zur Entwickekmg des hautigen Bogenganges des inneren Ohres.

Sitzungsber. Akad. Miinchen, 1888.

Literature — Chapter X

The Alimentary Tract and Its Appendages

A. The Oral Cavity and Organs

Fraisse, p., Ueber Zahne bei Vogeln. Vortrag, geh. in der phys.-med.

Ges. Wiirzburg, 1880. Gardiner, E. G., Beitrage zur Kenntniss des Epitrichiums und der Bikkmg

des Vogelscknabels. Inaug. Dissert. Leipzig, 1884. Arch. mikr. Anat., Bd. XXIV, 1884. Gauff, E., Anat. L^ntersuchungen iiber die Nervenversorgung der Mund und Nasenhohledrusen der Wirbekiere. Morph. Jahrb., Bd. XIV, 1888. GiACOMiNi, E., Sulle glanduH sakvari degk uccelk. Richerche anatomico embrologiche. Monit. zook Itak, Anno 1, 1890.


GoppERT, E., Die Bedeutimg der Zunge ftir den secundaren Gaumen und den

Ductus naso-pharyngeus. Beobachtungen an Reptilien und Vogeln.

Morph. Jahrb., Bd. XXXI, 1903. Kallius, E., Die mediane Thyreoideaanlage und ihre Beziehung zum Tuber culum impar. Verb. anat. Ges., 17. Vers., 1903.

Beitrage zur Entwickelung der Zunge. Verb. anat. Ges., 15. Vers.

Bonn, 1901. Manno, Andrea, Sopra il niodo onde si perfora e scompare le membrana

faringea negli embrioni di polio. Richerche Lab. Anat. Roma, Vol.

IX, 1902. Oppel, a., Lehrbuch der vergleichenden mikroskopischen Anat. der Wir beltiere. Jena, 1900. Reichel, p., Beitrag zur Morphologie der ^Mundhohlendriisen der Wirbel thiere. Morph. Jahrb., Bd. VIII, 1883. Rose, C., Ueber die Zahnleiste und die Eischwiele der Sauropsiden. Anat.

Anz., Bd. VII, 1892. Sluiter, C. p., Ueber den Eizahn und die Eischwiele einiger Reptilien.

Morph. Jahrb., Bd. XX, 1893. Yarrell, W., On the Small Horny Appendage to the Upper Mandible in

Very Young Chickens. Zool. Journal, 1826.

B. Derivatives of the Emhryonic Pharynx

van Bemmelen, J. F., Die Visceraltaschen und Aortenbogen bei Reptilien

und Vogeln. Zool. Anz., 1886. His, W., Ueber den Sinus praecervicalis und die Thymusanlage. Arch.

Anat. u. Entw., 1886.

Schlundspalten und Thymusanlage. Arch. Anat. u. Entw., 1889. Der Tractus Thyreoglossus und seine Beziehung zum Zungenbein.

Arch. Anat. u. Entw., 1891. Kastschenko, N., Das Schlundspaltengebiet des Hiihnchens. Arch. Anat.

und Entw., 1887. LiESSNER, E., Ein Beitrag zur Kenntniss der Kiemenspalten und ihrer An lagen bei amnioten Wirbelthieren. Morph. Jahrb., Bd. XIII, 1888. Mall, F. P., Entwickelung der Branchialbogen und Spalten des Hiihnchens.

Arch. Anat. und Entw., 1887. DE Meuron, p., Recherches sur le developpement du thymus et de la glande

thyreoide. Dissertation, Geneve, 1886. MiJLLER, W., Ueber die Entwickelung der Schilddriise. Jen. Zeitschr., Bd.

VI, 1871. Seessel, a., Zur Entwickelungsgeschichte des Vorderdarms. Arch. Anat.

und Entw., 1877. Verdun, M. P., Sur les derives branchiaux du poulet. Comptes rendus

Soc. Biol., Tom. V. Paris, 1898.

Derives branchiaux chez les vertebres superieurs. Toulouse, 1898.


APPENDIX 455

C. (Esophagus, Stomach, Intestine

BoRNHAUPT, Th., Uritersuchiingen fiber die Entwickelung des Urogenital systems beim Huhnchen. Inaug. Diss. Riga, 1867. Cattaneo, G., Intorno a un recente lavoro sullo stomaco degli iiccelli. Pavia,

1888.

Istologia e sviluppo del apparato gastrico degli uceelli. Atti della

Soc. Ital. di Sc. Nat., Vol. XXVII, Anno 1884. Milano, 1885. Cazin, M., Recherches anatomiques, histologiques et embryologiques sur

I'appareil gastrique des oiseaux. Ann. Sc. Xat. Zool. 7 ser., Tom. IV,

1888.

Sur le developpement embryonnaire de Testomac des oiseaux. Bull.

de la societe philomathique de Paris. 7 ser., Tom. XI, Paris, 1887. Developpement de la couehe cornee du gesier du poulet et des glandes

qui la seeretent. Comptes rendus, T. CI, 1885. Cloetta, M., Beit rage zur mikroskopischen Anatomic des Vogeldarmes.

Archiv. mikr. Anat., Bd. XLI, 1893. Fleischmaxx, Albert, Morphologische studien uber Kloake und Phallus der

Amnioten. III. Die Vogel, von Dr. Carl Pomayer. Morph. Jahrb.,

Bel. XXX, 1902. Gasser, E., Beitrage zur Entwiekelungsgeschichte der Allantois, Miiller schen Gauge und des Afters. Frankfurt a. M., 1893.

Die Entstehung der Kloakenoffnung bei Hiihnerembryonen. Arch.

Anat. u. Entw., 1880. Maurer, F., Die Entwickelung des Darmsystems. Handb. d. vergl. u.

exp. Entw.-lehre der Wirbeltiere. 11^, 1902. v. MiHALCovics, v., Untersuchungen liber die Entwickelung des Harn- und

Geschlechtsapparates der Amnioten. Internat. Monatschr. Anat. u.

Phys., Bd. II, 1885-1886. MiNOT, C. S., On the Solid Stage of the Large Intestine in the Chick. Journ.

Bos. Soc. Med. Sc, Vol. IV, 1900. Pomayer, Carl. See Fleischmann. Retterer, E., Contributions a I'etude du cloaque et de la bourse de Fabricius

chez des oiseaux. Journ. de I'anat. et de la phys. 21 An. Paris, 1885. Seyfert, Beitrage zur mikroskopischen Anatomic und zur Entwiekelungsgeschichte der blinden Anhange des Darmcanals bei Kaninchen, Taube

unci Sperling. Inaug. Diss. Leipzig, 1887. ScHW^\RZ, D., Untersuchungen des Schwanzendes bei den Embryonen der

Wirbeltiere. Zeitschr. wiss. Zool., Bd. XL VIII, 1889. Stieda, L. LudwiG, L^eber den Bau und die Entwickelung der Bursa Fabricii.

Zeitschr. wiss. Zool., Bd. XXXIV, 1880. Swenander, G., Beitrage zur Kenntniss des Kropfes der Vogel. Zool. Anz.,

Bd. XXIT, 1899. Weber, A., Quelques faits concernant le developpement de Tintestin moyen,

et de ses glandes annexes chez les oiseaux. C. R. Soc. Biol., T. LIV. Paris,

1902. Wenckebach, K. F., De Ontwikkeling en de bouw der Bursa Fabricii. Inaug. Dissert. Leiden, 1888.


456 APPENDIX

D. Liver and Pancreas

Bracket, A., Die Entwickelung unci Histogenese der Leber und des Pancreas.

Ergebnisse d. Anat. u. Entw.-gesch., 1896. Brouha, M., Recherches sur le developpement du foie, du pancreas, de la

cloison mesenterique et des cavites hepato-enteriques chez les oiseaux.

Journ. de Tanat. et phys., T. XXXIV. Paris, 1898.

Sur les premieres phases du foie et sur revolution des pancreas ven traux chez les oiseaux. Anat. Anz., Bd. XIV, 1898. Choronschitzky, B., Die Entstehung der Milz, Leber, Gallenblase, Bauch speicheldriise und des Pfortadersystems bei den verschiedenen Abthei lungen der Wirbelthiere. Anat. Hefte, Bd. XIII, 1900. Felix, W., Zur Leber und Pancreasentwickelung. Arch. Anat. u. Entw., 1892. Frobeen, F., Zur Entwickelung der Vogelleber. Anat. Hefte, 1892. GoTTE, Alex., Beitrage zur Entwickelungsgeschichte des Darmcanals im

Huhnchen. Tubingen, 1867. Hammar, G. a., Ueber Duplicitat ventraler Pancreasanlage. Anat. Anz.,

Bd. XIII, 1897.

Ueber einige Hauptztige der ersten embryonalen Leberentwickelung.

Anat. Anz., Bd. XIII, 1897.

Einige Plattenmodelle zur Beleuchtung der fruheren embryonalen

Leberentwickelung. Arch. Anat. u. Entw., 1893. MiNOT, C. S., On a Hitherto Unrecognized Form of Blood-Circulation without

Capillaries in the Organs of Vertebrata. Proc. Boston Soc. of Nat.

Hist., Vol. XXIX, 1900. ScHREiNER, K. E., Beitrage zur Histologic und Embryologie des Vorder darms der Vogel. Zeitschr. wiss. ZooL, Bd. LXVIII, 1900. Shore, T. W., The Origin of the Liver, Journ. of Anat. and Phys., Vol. XXV,

1890-91. Saint-Remy, Sur le developpement du pancreas chez les oiseaux. Rev.

biol. du Nord de la France. Annee V, 1893.

E. The Respiratory Tract

Bar, M., Beitrage zur Kenntniss der Anatomic und Physiologic der Athemwerkzeuge bei den Vogeln. Zeitschr. wiss. Zool., Bd. LXI, 1896.

Bertelli, D., Sviluppo de sacchi aeriferi del polio. Divisione della cavita celomatica degli uccelli. Atti della Societa Toscana di scienze natural! residente in Pisa. Memorie, Vol. XVII, 1899.

Blumsteix-Judina, Beila, Die Pneumatisation des Markes der Vogelknochen. Anat. Hefte, Abth. I, Bd. XXIX (Heft 87), 1905.

Camp ANA, Recherches d 'anatomic de physiologic, et d 'organogenic pour la determination des lois de la genese et de revolution des especes animals. I. Memoire. Physiologic de la respiration chez les oiseaux. Anatomic de I'appareil pneumatique puhnonnaire, des faux diaphragmes, des seremus et de I'intestin chez le poulet. Paris, Masson, 1875.

Goeppert, E., Die Entwickelung der luftfiihrenden Anhange des Vorderdarms. Handbuch d. vergl. u. exp. Entw.-lehre der Wirbeltiere, Bd. II, T. 1, 1902.


APPENDIX 457

LocY, W. A. and Larsell, O., The Embryology of the Bird's Lung, Based on Observations of the Domestic Fowl. Am. Journ. of Anat., Vol. 19, pp. 447-504, and Vol. 20, pp. 1-44, 1916.

Rathke, M. H., Ueber die Entwickelung der Atemwerkzeuge bei den Vogeln und Saugetieren. Nov. Act. Acad. Caes. Leop. Car., T. XIV. Bonn, 1828.

Selenka, E., Beitrage zur Entwickelungsgeschichte der Luftsiicke des Huhnes. Zeitschr. wiss. Zool., Bd. XVI, 1866.

Strasser, H., Die Luftsacke der Vogel. Morph. Jahrb., Bd. Ill, 1877.

Weber, A., et Buvignier, A., Les premieres phases du developpement du poumon chez les embryons de poulet. Comptes rendus hebd. des seances de la societe de Biologie, Vol. LV. Paris, 1903.

WuNDERLiCH, L., Beitrage zur vergleichenden Anatomie und Entwickelungsgeschichte des unteren Kehlkopfes der Vogel. Nova Acta Acad. Caes. Leop. Carol. Germanicae, Bd. XL VIII, 1884.


LITERATURE — CHAPTER XI

Beddard, F. E., On the Oblique Septa ("Diaphragm" of Owen) in the Passerines and some other Birds. Proc. Zool. Soc. London, 1896.

Bertelli, D., Sullo sviluppo del diaframma dorsale nel Polio. Nota preventiva. Monit. Zool. Ital., Anno IX, 1898.

Contributo alia morfologia ed alio sviluppo del diaframma ornitico. Ibid., 1898.

Bracket, A., Die Entwickelung der grossen Korperhohlen imd ihre Trennung von einander, etc. Ergebnisse d. Anat. u. Entw.-gesch., Bd. VII, 1897.

Broman, Ivar, Die Entwickelungsgeschichte der Bursa omentalis und ahnlicher Recessbildungen bei den Wirbeltieren. Wiesbaden, 1904.

B-ROUHA, M. See Chap. X.

Butler, G. W., On the Subdivision of the Body Cavity in Lizards, Crocodiles and Birds. Proc. Zool. Soc. London, 1889.

Choronschitzky, B. See Chap. X.

Dareste, C, Sur la formation du mesentere et de la gouttiere intestinale dans Tembryon de la poule. Comptes rendus, T. CXII, 1891.

HocHSTETTER, F., Die Entwickelung des Blutgefasssystems. Handbuch der vergl. und exp. Entw.-lehre der Wirbeltiere. IIP, 1903.

Janosik, J., Le pancreas et la rate. Bibliographic Anat. Annee 3. Paris, 1895.

LocKWOOD, C. B., The Early Development of the Pericardium, Diaphragm and Great Veins. Phil. Trans. Roy. Soc, London, Vol. CLXXIX, 1889.

Mall, F. P., Development of the Lesser Peritoneal Cavity in Birds and Mammals. Journ. Morph., Vol. V, 1891.

Maurer, F., Die Entwickehmg des Darmsystems. Handbuch d. vergl. u. exp. Entw.-lehre d. Wirbeltiere, Vol. II, 1906.

Peremeschko, LTeber die Entwickelung der Milz. Sitzungsber. d. Akad. d. Wiss. in Wien, math., naturwiss. Klasse, Bd. LVI, Abth. 2, 1867.

Ravn, E., Die Bildung des Septum transversum beim Hiihnerembryo. Arch. Anat. u. Entw., 1896. See also Anat. Anz., Bd. XV, 1899.


458 APPENDIX

Reichert, Entwickelungsleben im Wirbeltierreich. Berlin, 1840. Remak, Untersuchungen liber die Entwickelung des Wirbeltierreichs, p. 60,

1850-1855. UsKOW, W., Ueber die Entwickelung des Zwerchfells, des Pericardium und

des Coeloms. Arch. mikr. Anat., Bd. XXII, 1883. WoiT, O., Zur Entwickelung der Milz. Anat. Hefte, Bd. IX, 1897.

LITERATURE — CHAPTER XII

V. Baer, K. E., Ueber die Kiemen und Kiemengefasse im den Embryonen

der Wirbeltiere. Meckel's Archiv., 1827. VAN Bemmelen, J., Die Visceraltaschen und Aortenbogen bei Reptilien und

Vogeln. Zool. Anz., 1886. Boas, J. E. V., Ueber die Aortenbogen der Wirbeltiere. Morph. Jahrb.,

Bd. XIII, 1887. Brouha. See Chap. X. HocHSTETTER, F., Die Entw^ickelung des Blutgefasssystems (des Herzens

nebst Herzbeutel und Zwerchfell, der Blut- und Lymphgefasse, der

Lymphdriisen und der Milz in der Reihe der Wirbeltiere). Handbuch

der vergl. und exp. Entwickelungslehre der Wirbeltiere. IIP, 1903. Beitrage zur Entwickelungsgeschichte des Venensystems der Amnioten.

I. Hiihnchen. Morph. Jahrb., Bd. XIII, 1888.

Ueber den Ursprung der Arteria Subclavia der Vogel. Morph. Jahrb,

Bd. XVI, 1890.

Entwickelung des Venensystems der Wirbeltiere. Ergeb. der Anat.

u. Entw., Bd. Ill, 1893. HuscHKE, E., Ueber die Kiemenbogen und Kiemengefasse beim bebriiteten

Hiihnchen. Isis, Bd. XX, 1827. Langer, a., Zur Entwickelungsgeschichte des Bulbus cordis bei Vogeln und

Saugetieren. Morph. Jahrb., Bd. XXII, 1894. LiNDES, G., Ein Beitrag zur Entwickelungsgeschichte des Herzens. Dissertation. Dorpat, 1865. LocY, W. A., The Fifth and Sixth Aortic Arches in Chick Embryos with

Comments on the Condition of the Same Vessels in other Vertebrates.

Anat. Anz., Bd. XXIX, 1906. Mackay, J. Y., The Development of the Branchial Arterial Arches in Birds,

with Special Reference to the Origin of the Subclavians and Carotids.

Phil. Trans. Roy. Soc, London, Vol. CLXXIX, 1889. Masius, J., Quelques notes sur le developpement du coeur chez le poulet.

Arch. Biol., T. IX, 1889. Miller, W. S., The Development of the Postcaval Veins in Birds. Am.

Journ. Anat., Vol. II, 1903. PopoFF, D., Die Dottersackgefasse des Huhnes. Wiesbaden, 1894. Rathke, H., Bemerkungen iiber die Entstehung der bei manchen Vogeln

und den Krokodilen vorkommenden unpaaren gemeinschaftlichen Carotis.

Arch. Anat. u. Phys., 1858. Rose, C, Beitrage zur vergleichenden Anatomie des Herzens der Wirbeltiere. Morph. Jahrb., Bd. XVI, 1890.


APPENDIX 459

Rose, C, Beitrage zur Entwickelungsgeschichte des Herzens. Inaug. Dissert.

Heidelberg, 1888. ToNGE, Morris, On the Development of the Semilunar Valves of the Aorta

and Pulmonary Artery of the Chick. Phil. Trans. Roy. Soc, London,

Vol. CLIX, 1869. Twining, Granville H., The Embryonic History of the Carotid Arteries

in the Chick. Anat. Anz., Bd. XXIX, 1906. ViALLETON, L., Developpement des aortes posterieures chez I'embryon de

poulet. C. R. Soc. Biol., T. III. Paris, 1891.

Developpement des aortes chez Tembryon de poulet. Journ. de

Tanat. et phys., T. XXVIII, 1892. ZucKERKANDL, E., Zur Anat. und Entwickelungsgeschichte der Arterien des

Unterschenkels und des Fusses. Anat. Hefte, Bd. V, 1895.

Zur Anatomie und Entwickelungsgeschichte der Arterien des Vor derarmes. Anat. Hefte, Bd. IV, 1894.

LITERATURE — CHAPTER XIII

Abraham, K., Beitrage zur Entwickelungsgeschichte des Wellensittichs.

Anat. Hefte, Bd. XVII, 1901. Balfour, F. M., On the Origin and History of the Urogenital Organs of

Vertebrates. Journ. of Anat. and Physiol., Vol. X, 1876. Balfour and Sedgwick, On the Existence of a Rudimentary Head Kidney

in the Embryo Chick. Proc. R. Soc, London, Vol. XXVII, 1878. On the Existence of a Head Kidney in the Embryo Chick and on

Certain Points in the Development of the Miillerian Duct. Quar. Journ.

Micr. Sc, Vol. XIX, 1879. BoRNHAUPT, Th., Zur Entwickelung des Urogenitalsystems beim Huhnchen.

Inaug. Diss. Dorpat, 1867. Brandt, A., Ueber den Zusammenhang der Glandula suprarenalis mit dem

parovarium resp. der Epididymis bei Hiihnern. Biolog. Centralbl.,

Bd. IX, 1889.

Anatomisches und allgemeines liber die sog. Hahnenfedrigkeit und

liber anderweitige Geschlechtsanomalien der Vogel. Zeitschr. wiss. Zool.,

Bd. XL VIII, 1889. Felix, W., Zur Entwickelungsgeschichte der Vorniere des Huhnchens Anat. Anz., Bd. V, 1890. Felix und Buhler, Die Entwickelung der Ham- und Geschlechtsorgane.

]. Abschnitt — Die Entwickelung des Harnapparates, von Prof. Felix.

Handbuch der vergl. u. exper. Entw.-lehre der Wirbeltiere, HIS 1904. FiRKET, Jean, Recherches sur I'organogenese des glands sexuelles chez les

oiseaux. Arch, de Biol. Tome 29, pp. 201-351. PI. 5, 1914. FuRBRiNGER, M., Zur vcrgleichendeu Anatomie und Entwickelungsgeschichte

der Excretionsorgane der Vertebraten. Morph. Jahrb., Bd. IV, 1878. Fusari, R., Contribution a I'etude du developpement des capsules surre nales et du sympathetique chez le poulet et chez les mamniiferes. Archives. Hal. de biologic, T. XVI, 1892.


460 APPEXDIX

Gasser, E., Beitrage zur Entwickelungsgeschichte der Allantois, der Muller schen Gange imd des Afters. Frankfurt a. M., 1874.

Die Entstehung des Wolff'schen Ganges beim Huhn. Sitz.-ber.

Naturf. Ges., Marburg, Jahrg. 1875.

Beobachtungen uber die Entstehung des Wolff'schen Ganges bei

Embryonen von Hiihnern und Gansen. Arch. mikr. Anat.. Bd. XIV, 1877. Gasser, E., und Siemmerling, Beitrage zur Entwickekmg des Urogenitalsys tems bei den Huhnerembryonen. Sitz.-ber. Naturf. Ges., Marburg, 1879. Gerhardt, U., Zur Entwickelung der bleibenden Niere. Arch. mikr. Anat.,

Bd. LVII, 1901. HocHSTETTER, F., Zur Morphologie der Vena cava inferior. Anat. Anz., Bd. Ill,

1888. Hoffmann, C. K., Etude sur le developpement de I'appareil urogenital des

oiseaux. Verhandelingen der Koninklyke Akademie van Wetenschap pen. Amsterdam, Tweede Sectie, Vol. I, 1892. Janosik, J., Bemerkungen iiber die Entwickelung der Nebennieren. Archiv.

mikr. Anat., Bd. XXII, 1883.

Histologisch-embryologische Untersuchungen iiber das Urogenital system. Sitzungsber. Akad. Wiss. Wien, math.-nat. Kl., Bd. XCI,

3. Abth., 1885. KosE, W., Ueber die Carotisdriise und das "Chromaffine Gewebe" der Vogel.

Anat. Anz., Bd. XXV, 1904. KowALEvsKY, R., Die Bildung der Urogenitalanlage bei Huhnerembryonen.

Stud. Lab. Warsaw Univ., II, 1875. KuPFFER, C, Untersuchungen iiber die Entwickelung des Harn- und Ge schlechtssystems. Arch. mikr. Anat., Bd. I, 1865; and ibid. Bd. II, 1866. V. MiHALCOVics, v., Untersuchungen iiber die Entwickelung des Harn und Geschlechtsapparates der Amnioten. Intern. Monatschr. Anat.

und Phys., Bd. II, 1885-1886. Miner viNi, R., Des capsules surrenales: Developpement, structure, fonc

tions. Journ. de Tanat. et de la phys, An. XL. Paris, 1904. NussBAUM, M., Zur Differenzierung des Geschlechtes im Thierreich. Arch.

mikr. Anat., Bd. XVIII, 1880.

Zur Entwickelung des Geschlechts beim Huhn. Verh. anat. Ges., Bd

XV, 1901.

Zur Riickbildung embryonaler Anlagen. Arch. mikr. Anat., Bd

LVII, 1901.

Zur Entwickelung des Urogenitalsystems beim Huhn. C. R. Ass.

d. An. Sess., 5. Liege, 1903. Poll, H., Die Entwickelung der Nebennierensysteme. Handbuch der

vergl. und exper. Entwickelungslehre der Wirbeltiere. III^ 1906. Prenant, a., Remarques a propos de la constitution de la glande genitale

indifferente et de I'histogenese du tube seminifere. C. R. Soc. biol.,

Ser. 9, T. II, 1890. Rabl, H., Die Entwickelung und Struktur der Nebennieren bei den Vogeln.

Arch. mikr. Anat., Bd. XXXVIII, 1891. Renson, G., Recherches sur le rein cephalique et le corps de Wolff chez les

oiseaux et les mammiferes. Arch. mikr. Anat., Bd. XXII, 1883.


APPENDIX 461

RucKERT, J., Entwickelung der Excretionsorgane. Ergebnisse der Anat.

u. Entw.-gesch., Bd. I, 1892. ScHREixER, K. E., Ueber die Entwickelung der Amniotenniere. Zeitschr.

wiss. Zool., Bd. LXXI, 1902. Sedgwick, A., Deve opment of the Kidney in its Relation to the Wolffian Body in the Chick. Quart. Journ. IMicr. Sc, Vol. XX, 1880.

On the Early Development of the Anterior Part of the Wolffian Duct and Body in the Chick, together with Some Remarks on the Excretory System of Vertebrata. Quart. Journ. Micr. Sc, Vol. XXI, 1881. Semon, Richard, Die indifferente Anlage der Keimdriisen beim Htihnchen und ihre Differenzierung zum Hoden. Jen. Zeitschr. Naturwiss., Bd. XXI, 1887. SouLiE, E. H., Recherches sur le developpement des capsules surrenales chez les vertebres superieurs. Journ. de I'anat. et phys., Paris, An. XXXIX, 1903. Swift, Charles H., Origin and Early History of the Primordial GermCells in the Chick. American Journal of Anat., Vol. 15, pp. 483516, 1914.

Origin of the Definitive Sex-Cells in the Female Chick and their Relation to the Primordial Germ-Cells. ib. Vol. 18, pp. 441-470, 1915.

Origin of the Sex-Cords and Definitive Spermatogonia in the Male Chick, ib. Vol.20, pp. 375-410, 1916. Waldeyer, W., Eierstock und Ei. Ein Beitrag zur Anatomie und Ent wickelungsgeschichte der Sexualorgane. Leipzig, 1870. Weldon, On the Suprarenal Bodies of Vertebrates. Quar. Journ. Micr. Sc, Vol. XXV, 1884.

LITERATURE — CHAPTER XIV

Agassiz, L., On the Structure of the Foot in the Embryo of Birds. Proc

Boston Soc Nat. Hist., 1848. Bizzozero, G., Neue Untersuchungen iiber den Bau des Knochenmarks der

Vogeln. Arch. mikr. Anat., Bd. XXXV, 1890. See also Arch. Ital. de

Biol., T. XIV, 1891. Blu.mstein-Judixa, Beila, Die Pneumatisation des Markes der Vogelkno chen. Anat. Hefte, Abth. I, Bd. XXIX, 1905. Bracket, A., Etude sur la resorption de cartilage et le developpement des

OS longs chez les oiseaux. Internat. Monatschr. Anat. und Phys., Bd.

X, 1893. Braun, M., Entwickelung des Wellenpapageis. Arb. Zool. Zoot. Inst. Wiirz burg, Bd. V, 1881. Brulle et HuGUENY, Developpement des os des oiseaux. Ann. Sc. Nat.,

Ser. Ill, Zool. T. IV,1845. BuNGE, A., Untersuchungen zur Entwickelungsgeschichte des Beckengiirtels

der Amphibien, Reptilien und Vogel. Inaug. Diss. Dorpat. 1880. CuviER, Extrait d'un memoire sur les progres de I'ossification dans le sternum

des oiseaux. Ann. des Sc Nat., Ser. I, Vol. XXV, 1832. V. Ebner, v., Ueber die Beziehungen der Wirbel zu den LTrwirbel. Sitzungsber.

d. k. Akad. d. Wiss. Wien, math.-naturwiss. Kl., Bd. CI, 3. Abth.. 1892.


462 APPENDIX

Urwirbel und Neugliederiing der Wirbelsaule. Sitzungsber. d. k.

Akad. d. Wiss. Wien, Bd. XCVII, 3. Abth. Wien, 1889, Jahrg., 1888. Froriep, a., Zur Entwickelungsgeschichte der Wirbelsaule, insbesondere

des Atlas und Epistropheus und der Occipitalregion. I. Beobachtungen

an Hiihnerembryonen. Arch. Anat. u. Entw., 1883. Gaupp, E., Die Entwickelung des Kopfskelettes. Handbuch der vergl. u.

exper. Entw.-lehre der Wirbeltiere, Bd. 3, 1905.

Die Entwickelung der Wirbelsaule. Zool. Centralbl., Jahrg. Ill, 1896. Die Metamerie des Schadels. Ergeb. der Anat. u. Entw., 1897. Gegenbaur, C, Untersuchungen zur vergl. Anat. der Wirbelsaule bei

Amphibien und Reptilien. Leipzig, 1864.

Beitrage zur Kenntniss des Beckens der Vogel. Eine vergleichende

anatomische Untersuchung. Jen. Zeitschr. Med. u. Naturw., Bd. VI, 1871. Die Metamerie des Kopfes und die Wirbeltheorie des Kopfskelettes,

im Lichte der neueren Untersuchungen betrachtet und gepriift. Morph.

Jahrb., Bd. XIII, 1888. GoETTE, A., Die Wirbelsaule und ihre Anhange. Arch. mikr. Anat., Bd.

XV, 1878. Hepburn, D., The Development of Diarthrodial Joints in Birds and Mammals. Proc. R. Soc. Edinb., Vol. XVI, 1889. Also in Journ. of Anat.

and Phys., 1889. Jager, G., Das Wirbelkorpergelenk der Vogel. Sitzungsber. Akad. Wien,

Bd. XXXIII, 1858. Johnson, Alice, On the Development of the Pelvic Girdle and Skeleton

of the Hind Limb in the Chick. Quar. Journ. Micr. Sc, Vol. XXIII,

1883. KuLCZYCKi, W., Zur Entwickelungsgeschichte des Schultergiirtels bei den

Vogeln mit besonderer Berucksichtigung des Schliisselbeines (Gallus,

Columba, Anas). Anat. Anz., Bd. XIX, 1901. Leighton, V. L., The Development of the Wing of Sterna Wilsonii. Am.

Nat., Vol. XXVIII, 1894. LuHDER, W., Zur Bildung des Brustbeins und Schultergiirtels der Vogel.

Journ. Ornith., 1871. Mannich, H., Beitrage zur Entwickelung der Wirbelsaule von Eudyptes

chrysocome. Inaug. Diss. Jena, 1902. Mehnert, Ernst, LTntersuchungen liber die Entwickelung des Os Pelvis

der Vogel. Morph. Jahrb., Bd. XIII, 1887.

Kainogenesis als Ausdruck differenter phylogenetischer Energieen.

Morph. Arb., Bd. VII, 1897. Morse, E. S., On the Identity of the Ascending Process of the Astragalus

in Birds w'ith the Intermedium. Anniversary Mem. Boston Soc. Nat.

Hist., 1880. Norsa, E., Alcune richerche sulla morphologia dei membri anteriori degli

uccelli. Richerche fatte nel Laborat Anatomico di Roma e alti labora tori biologici, Vol. IV, fasc. I. Abstract in French in Arch. Ital. biol.,

T. XXII, 1894. Parker, W. K., On the Structure and Development of the Skull of the Common Fowl (Gallus domesticus). Phil. Trans., Vol. CLIX, 1869.


APPEXDIX 463

Parker, W. K., On the Structure and Development of the Birds' Skull.

Trans. Linn. Soc, 1876.

On the Structure and Development of the Wing of the Common Fowl.

Phil. Trans., 1888. Remak, R., Untersuchungen liber die Entwickelung der Wirbeltiere. Berlin,

1850-1855. Rosenberg, A., Ueber die Entwickelung des Extremitiitenskelets bei einigen

durch die Reduction ihrer Gliedmaassen charakteristischen Wirbeltiere.

Zeitschr. wiss. ZooL, Bd. XXIII, 1873. ScHAUiNSLAND, H., Die Entwickelung der Wirbelsaule nebst Rippen und

Brustbein. Handbuch der vergl. und exper. Entw.-lehre der Wirbeltiere, Bd. Ill, T. 2, 1905. Schenk, F., Studien liber die Entwickelung des knochernen Unterkiefers

der Vogel. Sitzungsber. Akad. Wien, XXXIV Jahrg., 1897. Schultze, O., Ueber Eml^ryonale und bleibende Segmentirung. Verh.

Anat. Ges., Bd. X. Berlin, 1896. Stricht, O. van der, Recherches sur les cartilages articulaires des oiseaux.

Arch, de biol., T. X, 1890. SuscHKiN, P., Zur Anatomic und Entwickelungsgeschichte des Schadels der

Raub vogel. Anat. Anz., Bd. XI, 1896.

Zur Morphologic des Vogelskeletts. (1) Schadel von Tinnunculus.

Nouv. Mem. Soc. Imp. des X'atur. de Moscow, T. X\T, 1899. ScHWARCK, W., Beitrage zur Entwickelungsgeschichte der Wirbelsaule bei

den Vogeln. Anat. Studien (Herausgeg. v. Hasse), Bd. I, 1873. WiEDERSHEiM, R., Ucbcr die Entwickelung des Schulter- und Beckenglirtels.

Anat. Anz., Bd. IV, 1889, and V, 1890. WiJHE, J. W. VAN, Ueber Somiten und Nerven im Kopfe von Vogel- und

Reptilienembryonen. Zool. Anz., Jahrg. IX, 1886.


INDEX


Abducens nerve, 267

Abducens nucleus, 262, 263

Abnormal eggs, 2.5

Accessory cleavage of pigeon's egg, 38, 43, 44

Accessory mesenteries, 340, 341

Acustico-facial ganglion complex, 159 160, 262, 268

Air-sacs, 326, 330, 331

Albumen, 18

Albumen-sac, 217, 224

Albuginea of testis, 397

Alecithal ova (see isolecithal)

Allantois, blood-supply of, 222; general, 217; inner wall of, 220; neck of, 143, 144, 316; origin of, 143, 144; outer wall of, 220; rate of growth, 221; structure of inner wall, 223; structure of outer wall, 223

Amnion, effect of rotation of embryo on, 140, 141, 142; functions of, 231; head fold of, 137, 139; later history of, 231; mechanism of formation, 139, 140; muscle fibers of, 231; origin of, 135; secondary folds of, 142

Amnio-cardiac vesicles, 92, 116

AmpuUse of semicircular canals, 291

Anal plate, 143, 182

See also cloacal membrane

Angioblast, 88

Anterior chamber of eye, 278

Anterior commissure of spinal cord, origin of, 244

Anterior intestinal portal, 95 (Fig. 49), 121, 132

Anterior mesenteric artery, 363

Aortic arches, 198, 199, 203, 358362 ; transformations of, 359-361

Appendicular skeleton, 434

Aqueduct of Sylvius, 251.

Archenteron, 55

Area opaca, 39, 50, 61, 86; pellucida, 39, 50, 61; vasculosa, 61, 86; vitellina, 61, 62, 86

Arterial system, 121, 126, 198, 199, 203, 204, 228, 358-363

Atlas, development of, 420

Atrium bursse omentalis, 344


Auditory nerve, 295; ossicles, 299, 432; pit, 168

Auricular canal, 354

Auriculo- ventricular canal, 348; division of, 355

Axis, development of, 420

Axones, origin of, 235

Basilar plate, 429

Beak, 302, 304

Biogenesis, fundamental law of, 4

Blastoderm, 17; diameter of unin cubated, 61; expansion of, 50, 53,

61 Blastopore, 55, 82 Blood-cells, origin of, 118 Blood-islands, origin of, 86, 89 Blood-vessels, origin of, 118 Body-cavity, 115, 205-210, 333 Bony labyrinth, 296 Brain, primary divisions of, 108;

early development of, 147, 156;

later development of, 244-252 Branchial arch, first, skeleton of, 432 Bronchi, 325, 326 Bulbus arteriosus, 198, 201, 202, 348;

fate of, 357 Bursa Fabricii, 314, 317, 319 Bursa omenti ma j oris, 344 Bursa omenti minoris, 344

Canal of Schlemm, 279

Cardinal veins, anterior, 200, 204,

205, 363; posterior, 200, 204, 205,

368 Carina of sternum, 427 Carotid arch, 361 Carotid, common, 362; external 359,

361 ; internal, 359-361 Carpus, 436, 437 Cartilage, absorption of, 408; bones,

definition, 407; calcification of,

409 Caval fold, 344 Cavo-coeliac recess, 344 Cavum sub-pulmonale, 342 Cell-chain hypothesis, 255 Cell theory, \

Central and marginal cells, 41, 42 Central canal of spinal cord, 242


465


466


INDEX


Cerebellum, 155, 251

Cephalic mesoblastic somites, 108, 269, 428

Cerebral flexures, 149, 245

Cerebral ganjilia, 157-162, 262

Cerebral hemispheres, origin of, 151; (see telencephalon)

Cervical flexure, 133, 245

Chalazee, 18

Chemical composition of parts of hen's egg, 20, 21

Chiasma opticus, 154, 249

Choanal, 215, 285

Chondrification, 408

Chorion, 135, 217, 218, 220

Choroid coat of eye. 279; fissure, 166, 281 ; plexus, 248

Chromaffin tissue, 404

Chronology, 64

Cilary processes, 272, 274

Circulation of blood, 121, 122, 197200, 372-376

Circulation of blood, changes at hatching, 376; completion of double, 355

Classification of stages, 64-67

Clavicle, 434, 435

Cleavage of ovum (hen), 39-43

Cleavage of ovum (pigeon), 43-47

Cloaca, 314-319; (see hind-gut)

Cloacal membrane, 315, 318; (see also anal plate)

Coeliac artery, 363

Coelome (see body-cavity)

Coenogenetic aspects of development, 6

Collaterals, origin of, 238

Collecting tubules of mesonephros, 379, 380

CoUiculus palato-pharyngeus, 398

Commissura anterior, 252; inferior, 252 ; posterior, 252 ; trochlearis, 252

Concrescence, theory of, 82, 84

Cones of growth, 235

Conjunctival sac, 279

Coprodseum, 315, 318, 319

Coracoid, 434, 435

Cornea, 278

Corpus striatum, 247

Corpus vitreum, 275

Cortical cords of suprarenal capsules, 405

Cranial flexure, 133, 245; nerves, 261

Cristse acusticse, 295

Crop, 312

Crural veins^ 372

Cushion septum, 355

Cuticle of sheU, 17

Cutis plate, 185, 188


Delimitation of embryo from blastoderm, 91

Dendrites, origin of, 236

Determinants, 7

Diencephalon, early development of, 152; later development of, 249

Dorsal aorta, origin of, 121

Dorsal longitudinal fissure and septum of spinal cord, 243, 244

Dorsal mesentery, 172, 342

Duct of Botallus, 359, 361, 376

Ducts of Cuvier, 200, 204, 207, 361

Ductus arteriosus (see duct of Botalus) ; choledochus (common bileduct), 181, 321; cochlearis, 293; cystico-entericus, 321 ; endolymphaticus, 169, 289; hepato-cysticus, 321; hepato-entericus, 321; venosus (see meatus venosus)

Duodenum, 310, 311

Ear, later development of, 288

Ectamnion, 138

Ectoderm and entoderm, origin of, 52

Ectoderm of oral cavity, limits of, 301

Egg, formation of, 22, 24, 25

Egg-tooth, 302, 303

Embryonic circulation, on the fou.rth day, 372-374; on the sixth day, 374; on the eighth day, 374-376

Embryonic membranes, diagrams of, 219, 220; general, 216; origin of, 135; summary of later historj^, 145

Endocardium, origin of, 119

Endolymphatic duct (see ductus endolymphaticus)

Endolymphatic sac (see saccus endolymphaticus)

Entobronch;, 327, 328

Entoderm, origin of, 52

Ependyma, origin of, 239

Epididymis, 391, 398

Epiphysis, 153, 249

Epiphyses (of long bones), 409

Epistropheus, development of, 420

Epithalamus, 251

Epithelial ceUs of neural tube, 233, 234

Epithelial vestiges of visceral pouches 309

Epoophoion, 401

Equatorial ring of lens, 277-278

Excentricity of cleavage, 41, 47

Excretory system, origin of, 190

External auditory meatus, 297, 300

External form of the embryo, 211

Eye, early development of, 164; later development of, 271

Eyelids, 279-280


INDEX


467


Facial region, development of the,

214, 215, 216 Facialis nerve, 268 Facialis nucleus, 262, 263 Femur, 440 Fertilization, 35 Fibula, 440

First segmentation nucleus, 36 Fissura metotica, 429 Foetal development, 11 Fold of the omentum, 344, 345 Follicles of ovary, 22, 26, 27, 28, 30,

400 Follicular cells, origin of, 27, 400 Foramen, interventricular, 353, 354;

of Monro, 247; of Winslow, 343;

ovale, 355 Foramina, interauricular, 355 Fore-brain, origin of, 108 Fore-gut, 91, 9'3, 172 Formative stuffs, 15 Funiculi prajcervicales, 307

Gall-bladder, 321

Ganglia, cranial and spinal, 156; cranial, 157, 158, 159, 262; spinal, later development of, 254, 257

Ganglion, ciliare, 266; geniculatum, 268; jugulare, 268; olfactorium nervi trigemini, 264; nodosum, 161, 268 ; ~ petrosum, 161, 268; of Remak, 257

Gastric diverticula of body-cavity, 340

Gastrulation, 53, 84

Genetic restriction, law of, 8

Genital ducts, development of, 401

Germ-cells, general characters of, 9-12; comparison of, 12-14

Germ-wall, 47, 48, 69, 90, 128, 129

Germinal cells of neural tube, 233, 234

Germinal disc, 11, 12, 35, 37, 39

Germinal epithelium, 391, 392, 399

Germinal vesicle, 27, 28

Gizzard, 313, 314

Glomeruli of pronephros, 192

Glossopharyngeus, ganglion complex of, 161, 262, 268; nerve, 268; nucleus, 262, 263

Glottis, 332

Gray matter of spinal cord, development of, 240; origin of, 239

Haemal arch of vertebrae, 416, 417

Harderian gland, 280

Hatching, 232

Head, development of, 213

Head-fold, origin of, 91

Head process, 73, 80


Heart, changes of position of, 348, 349; development on second and third days, 200-203; divisions of cavities of, 350 ; ganglia and nerves of, 259; later development of, 348; origin of, 119

Hensen's knot, 73

Hepatic veins, 366

Hepatic portal circulation, 366, 375

Hermaphroditism of embryo, 391

Heterotaxia, 133

Hiatus communis recessum, 343

Hind-brain, origin of, 108

Hind-gut, 143, 172

Hind-limbs, origin of skeleton, 438

Hoffmann's nucleus, 240

Holoblastic ova, 11, 12

Humerus, 436

Hyoid arch, 175: skeleton of, 432

Hyomandibular cleft, 174, 297

Hypoglossus nerve, 269

Hypophysis, 154, 249

Hypothalamus, 251

Ilium, 438, 439

Incubation, normal temperature for, 65, 66

Indifferent stage of sexual organs, 391

Infundibulum (of brain), 154, 249

Infundibulum (of oviduct). See ostium tubae abdominale

Interganglionic commissures, 156

Intermediate cell-mass, 114, 190

Interventricular sulcus, 348, 353

Intervertebral fissure, 412

Intestine, general development of, 310. 311

Iris, 272 : muscles of, 273, 274

Ischiadic veins, 372

Ischium, 438, 439

Isolecithal ova, 11

Isthmus, of brain, 155; of oviduct, 22

Jacobson, organ of, 286 Jugular vein, 363

Kidney, capsule of, 390; permanent, 384-389; secreting tubules of, 390

Lagena, 293

Lamina terminalis, 105, 152, 247, 248

Larva, 11

Laryngotracheal groove, 178, 331,

332 Ijarynx, 332 Latebra, 1 9

Lateral plate of mesoblast, 115 Lateral tongue folds, 305 Lens, 166, 276-278


468


INDEX


Lenticular zone of optic cup, 271

Lesser peritoneal cavity, 344

Ligamentum pectinatuni iridis, 279

Limiting sulci, 130

Lingual glands, 30G

Lip-grooves, 304

Liver, histogenesis of, 323; later development of, 319-323; origin and early development of, 179, 180, 181 ; origin of lobes of, 322 ; primarv ventral ligament of, 335

Lungs,^ 178, 326

Macula utriculi, sacculi, etc., 295

Malpighian corpuscles (mesonephric) origin of, 195

Mammillae of shell, 17

Mandibular aortic arch, 121, 122, 203, 204

Mandibular arch, skeleton of, 431

Mandibular glands, 306

Mantle layer of spinal cord, origin of, 239

Margin of overgrowth, 52, 57

Marginal notch, 60, 84, 85

Marginal velum, 235

Marrow of bone, origin of, 410

Maturation of ovum, 32

Meatus venosus, 199, 364, 366, 368

Medullary cords of suprarenal capsules, 405, 406

Medullary neuroblasts of brain, 262

Medullary plate, 95; position of anterior end of, in neural tube, 102, 103

Megaspheres, 59

Membrana reuniens, 418

Membrane bones, definition of, 407

]\Iembranes of ovum, 10

Membranous labyrinth, 289

Meroblastic ova, 11

Mesencephalon, 108, 155, 251

Mesenchyme, definition of, 116

Mesenteric artery, 363

Mesenteric vein, 366, 367

Mesenteries, 333

Mesentery, dorsal, 172, 342; of the vena cava inferior, 341

Mesoblast, gastral, 110; of the head, origin of, 116, 117; history of between 1 and 12 somites, 109; lateral plate of, 110, 115; of opaque area, origin of, 86, 88; origin of, 74, 78; paraxial, 110; prostomial, 110; somatic layer of, 115; splanchnic layer of, 115

Mesobronchus, 326, 327

Mesocardia lateralia, 200, 207, 334, 337

Mesocardium, origin of, 120


Mesogastrium, 309, 342, 343 Mesonephric arteries, 363 Mesonephric mesentery, 341 Mesonephric tubules, formation of,

195 Mesonephric ureters, 380 Mesonephros, later history of, 378;

origin and early history of, 194 197; see ^^'olffian body Mesothalamus, 251 Mesothelium, definition of, 116 Metacarpus, 436, 437, 438 Metamorphosis, 11 Metanephros, 384-389 Metatarsals, 441 Metathalamus, 251 Metencephalon, 155, 251 Mid-brain (see Mesencephalon) Mid-gut, 172, 181, 310 Mouth, 301 Miillerian ducts, 391; degeneration

in male, 402, 403; origin of, 401,

402, 403 Muscles of iris, 274 Muscle plate, 185, 186 Myelencephalon, 155, 252 Myocardium, origin of, 119 Myotome, 188

Nares, 286

Nephrogenous tissue, 195, 378; of

metanephros, 384, 387 Nephrotome, 114, 190 Neural crest, 156 Neural folds, 97, 99 Neural groove, 97 Neural tube, 95, 105 Neurenteric canal, 73, 82 Neuroblasts, 233-239; classes of, in

spinal cord, 244 Neurocranium, 427, 428 Neuroglia cells, origin of, 239, 240 Neuromeres, 108, 148, 152, 155 Neurone theory, 236, 255, 256 Neuropore, 101, 105 Notochord, later development of,

411 ff; oriirin of, 80; in the region

of the skull, 428

Oblicjue septum, 331, 342 Oculo-motor nerve, 265; nucleus,

262, 263 Odontoid process, origin of, 420 (Esophagus, 179, 310, 312 Olfactory lobe; 247 Olfactory nerve, 263 Olfactory pits, 169, 285 Olfactory A'estibule, 285 Omentum, development of, 343 Omphalocephaly, 120


INDEX


469


Omphalomesenteric arteries, 199,363; veins, 364-366

Ootid, 14

Opaque area, see area opaca

Optic cup, 165, 271 ; lobes, 251 ; nerve, 2S3, 284, 285; stalk, 149, 164, 284, 285; vesicles, accessory, 164

Optic vesicles, primary, 108, 164; secondary, 166

Ora serrata, 272

Oral cavity, 215, 216, 301

Oral glands, 306

Oral plate, 95, 173

Orientation of embryo on yolk, 25, 63

Ossification, 408-411; endochondral, 409; perichondral, 408

Ostium tubse abdominale, 23 ; development of, 402, 403; relation to pronephros, 402

Otocyst, 168; later development of, 289; method of closure, 168

Ovary, 22, 398-401; degeneration of right, 398

Oviducal membranes of ovum, 10

Oviduct, 22; later development of, 403

Ovocyte, 13, 26, 27

Ovogenesis, 12, 26

Ovogonia, 12, 26

Ovum, 2. 10; bilateral symmetry of, 15; follicular membrane of, 10; organization of, 14; polarity of, 14

Palate, 285, 299

Palatine glands, 306

Palingenetic aspects of development,

6 Pancreas, 181, 323-325, 347 Pander's nucleus, 19 Papilla; conjunctivie sclerse, 280 Parabronchi, 328 Parachordals, 428, 429 Paradidvmis, 391, 398 Paraphysis, 248 Parencephalon, 108, 153, 249 Parietal cavity, 92, 116, 207, 208,

333, 334 Paroophoron, 401 Pars copularis (of tongue), 305 Pars inferior iabyrinthi, 289,. 293 Pars superior lal)yrinthi, 2S9, 291 Parthenogenetic cleavage, 35 Patella, 441 Pecten, 281, 282 Pectoral girdle, 434-436 Pellucid area (see area pellucida) Pelvic girdle, 438-440 Periaxial cords, 158, 159, 161 Pericardiaco-peritoneal membrane,

338


Pericardial and pleuroperitoneal cavities, separation of, 333

Pericardium, closure of dorsal opening of, 337; formation of membranous, 338; see parietal cavity.

Periblast, 38, 43, 47; marginal and central 48; nuclei, origin of, 47, 48

Perichondrium, 408

Periderm, 304

Perilymph, 296, 297

Periosteum, 409

Peripheral nervous system, development of, 252

Pfliiger, cords of, 399

Phseochrome tissue, 404

Phalanges, 436, 438; of foot, 441; of wing, 438

Pharynx, derivatives of, 306; early development of, 93-95, 173; postbranchial portion of, 178

Phvlogenetic reduction of skeleton, 411

Physiological zero of development, 65

Physiology of development, 6

Pineal bodv, 153, 249

Placodes, 160, 161

Pleural and peritoneal cavities, separation of, 340

Pleural grooves, 208, 209

Pleuro-pericardial membrane, 338

Pleuroperitoneal membrane, 326; septum, 340, 341

Plica encephali ventralis, 149, 245

Plica mesogastrica, 341, 344, 368

Pneumato-enteric recesses, 209, 340

Pneumatogastric nerve, 268

Polar bodies, 13, 34

Polyspermy, 35, 36, 37

Pons, 252

Pontine flexure, 149, 245

Postanal gut, 182

Postbranchial bodies, 307, 309

Posterior intestinal portal, 132

Postotic neural crest, 160, 161

Precardial plate, 334, 338

Preformation, 6

Pre-oral gut, 174

Pre-oral visceral furrows, 174, 175

Preotic neural crest, 158

Primitive groove, 72

Primitive intestine, 55

Primitive knot, 73

Primitive mouth, 55, 82

Primitive ova, 26, 392, 399

Primitive pit, 73

Primitive plate, 73

Primitive streak, 69; interpretation of, 82; origin of, 74; relation to embryo, 85

Primordia, embryonic, 8


470


INDEX


Primordial cranium, development of,

428 Primordial follicle, 27 Proamnion, 86, 138 Procoracoid, 435 Proctoda^um, 170, 314, 319 Pronephros, 190-193 Pronucleus male and female, 34, 36 Prosencephalon, 108, 149 Proventriculus, 313 Pubis, 438, 439 Pulmo-enteric recesses (see pneu mato-) Pulmonary arteries, 359 Pupil of eye, 166, 272

Radius, 436

Ramus communicans, 254, 257, 259

Recapitulation theory, 3; diagram of, 5

Recessus hepatico-entericus, 343 ; recessus mesenterico-eutericus, 343; recessus opticus, 153; recessus pleuro-peritoneales, 340; recessus pulmo-hepatici, 340; recessus superior sacci omenti, 340

Rectum, 317

Renal corpuscles, 378, 383

Renal portal circulation, 369, 372, 375

Renal veins, 372

Reproduction, development of organs of, 390-403 ^

Respiratory tract, 178, 325

Rete testis, 398

Retina, 274, 275

Retinal zone of optic cup, 271

Rhombencephalon, 108, 155

Ribs, development of, 424, 425

s (abbreviation for somites), 67

Sacrum, 424

Sacculus, 293, 294

Saccus endolymphaticus, 169, 289, 290

Saccus infundibuli, 249

Scapula, 434, 435

Sclerotic coat of eye, 279

Sclerotomes, and vertebral segmentation, 412; components of, 412; occipital, 428; origin of, 185, 186

Seessell's pocket, 174

Segmental arteries, 122, 199, 362

Segmentation cavity, 43, 47, 53 (see also subgerminal cavity)

Semeniferous tubules, 398

Semicircular canals, 291

Semi-lunar valves, 352

Sensory areas of auditory labyrinth, origin of, 296


Septa of heart, completion of, 355,

356, 357 Septal gland of nose, 287 Septum aortico-pulmonale, 351, 352; of auricular canal, 355 ; bulboauricular, 353; cushion, 351, 355; interauricular, 351, 354; interventricular, 351, 353, 354; of sinus venosus, 358

Septum transversum, 208, 209, 334; derivatives of, 339; lateral closing folds of, 334, 337 ; median mass of, 335

Septum trunci et bulbi arteriosi, 351

Sero-amniotic connection, 138, 143, 217

Sexual cords, 393, 394; of ovary, 398; of testis, 395

Sexual differentiation, 394, 395

Sheath cells, 255

Shell, structure of, 17

Shell membrane, 18

Sickle (of Roller), 71

Sinu-auricular aperture, 357, 358

Sinu-auricular valves, 358

Sinus terminalis 86 (see also vena terminalis)

Sinus venosub, 197, 200, 201, 357; horns of, 358; relation to septum transversum, 339

Skeleton, general statement concerning origin, 407

Skull, chondrification of, 429-432; development of, 427; ossification of, 432, 433, 434

Somatopleure, 62, 115

Somite, first, position in embryo. 111

Somites, of the head, 114; mesoblastic, origin of, 110, 111; mesoblastic, metameric value of, 184; primary structure of, 114

Spermatid, 13

Spermatocyte, 13

Spermatogenesis, 12

Spermatogonia, 13

Spermatozoa, period of life Avithin oviduct, 35

Spermatozoon, 9

Spina iliaca, 440

Spinal accessory nerve, 269

Spinal cord, development of, 239

Spinal nerves, components of, 254; development of, 252, 255; bomatic components of, 254; splanchnic components of, 256

Splanchnocranium, 427

Splanchnopleure, 62, 115

Spleen, 345-347

Spongy layer of shell, 17

Stapes, 300


INDEX


471


Sternum, development of, 425-427

Stigma of follicle, 25

Stomach, 179, 313

Stomodaeum, 170, 173

Stroma of gonads, 393 ; of testis, 397

Subcardinal veins, 368, 369

Subclavian artery, 362

Subclavian veins, 363, 364

Subgerminal cavity, 53, 61, 69

Subintestinal vein, 367

Subnotochordal bar, 416, 418

Sulcus lingualis, 298

Sulcus tubo-tympanicus, 298

Supraorbital sinus of olfactory cavity, 285

Suprarenal capsules, 403-406

Sutura cerebralis anterior, 103-105; neurochordalis seu ventralis, 105; terminalis anterior, 105

Sympathetic nervous system, 256261; relation to suprarenals, 406

Sympathetic trunks, primary, 257; secondary, 258

Synencephalon, 108, 153, 249

Syrinx, 332

Tables of development, 68

Tail-fold, 131

Tarsuh, 441

Tectum lobi optici, 251

Teeth, 304

Tela choroidea, 152

Telencephalon and diencephalon,

origin of, 150 Telencephalon, later development of,

245-249; medium, 151, 245 Telolecithal, 11 Ten somite embryo, description of,

122 Testis, 395-398 Tetrads, 33

Thalami optici, 154, 251 Thymus, 308 Thyroid, 178, 307 Tongue, 305 Torus transversus, 248 Trabeculee, of skull, 428, 429; of

ventricles, 353 Trachea, 331, 332 Trigeminal ganglion complex, 160,

267 Trigeminus nerve, 267 ; nucleus (motor), 262, 263 Trochlearis nerve, 266; nucleus, 262,

263 Truncus arteriosus, 198 Tubal fissure, 298, 301 Tubal ridge, 401

Tuberculum impar (of tongue), 305 Tuberculum posterius, 249


Tubo-tympanic cavity, 297-300

Tubules of mesonephros, degeneration of, 380-382; formation of, 195-196; primary, secondary, tertiary, 379, 380

Turbinals, 285, 286, 431

Turning of embryo, 133

Tympanum, 297, 300

Ulna, 436

Umbilical arteries, 363; veins, 367,

368 Umbilicus, 144; of yolk-sac, 216 UnincuVjated blastoderm, structure

of, 69 Ureter, origin of, 384 Urinogenital ridge, 390, 391; system,

later development of, 378, etc. Uroda}um, 314, 319 Uterus, 22 Utriculus, 291, 292 Uvea, 273

Vagina, 22

Vagus, ganglion complex of, 161; nerve, 268; nucleus, 262, 263

Variability, embryonic, 64

Vas deferens, 401

Vasa efferentia, 398

Vascular system, anatomy of, on fourth day, 197-200; origin of, 117

Venous system, 127, 199, 204, 205, 228, 363-372

Velum transversum, 150, 248

Vena cava, anterior, 363, 364; inferior, 368-372

Vena porta sinistra, 367

Vena terminalis, 228; see also sinus terminalis

Ventral aorta, 121

Ventral longitudinal fissure of spinal cord, 243

Ventral mesentery, 131, 182, 343

Vertebrae, articulations of, 421; coalescence of, 424; costal processes of, 418; hypocentrum of, 418; intervertebral ligaments of, 421; ossification of, 421-424; pleurocentrum of, 418; stage of chondrification of, 418; suspensory ligaments of, 421 ;

Vertebral column, 411; condition on fourth day, 414; condition on fifth day, 415, 417; condition on seventh and eighth days, 418, 420; membranous stage of, 414 Vertebral segmentation, origin of,

412 ff Visceral arches, 175; clefts, 174, 307; furrows, 174; pouches, 174;


472


INDEX


/


pouches, early development of, 175178; pouches, fate of, 307, 308

Vitelline membrane, 10, 30, 31

Vitreous humor, 275


ongm


White matter of spinal cord,

of, 239, 241 Wing, origin of skeleton of, 434, 436 Wolffian body (see mesonephros) ; atrophy, 380, 382, 401; sexual and non-sexual portions, 396; at ninetv-six hours, 379; on the sixth^day, 382; on the eighth day, 382, 383 ; on the eleventh day, 385


Wolffian duct, 191, 193, 194, 391, 401

Yolk, 17, 19; formation of, 29 Yolk-sac, 143, 225-231; entoderm

of, 50; blood-vessels of, 227-230;

septa of, 225-227; ultimate fate

of, 230, 231 Yolk-spheres, 19, 20 Yolk-stalk, 132, 225

Zona radiata, 10, 30, 31 Zone of junction, 52, 57 Zones of the blastoderm, 127-129

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