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| THE DEVELOPMENT OF THE CHICK - AN INTRODUCTION TO EMBRYOLOGY | | {{Review - Lillie’s Development of the Chicken collapsetable}} |
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| | {| class="wikitable mw-collapsible mw-collapsed" |
| | ! Review - Lillie’s Development of the Chicken - an Introduction to Embryology 3rd Edn. (1952) |
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| | | 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. |
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| | 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. |
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| | 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. |
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| | 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). |
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| | 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. |
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| | 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. |
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| | 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. |
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| | [[Embryology History - William Hamilton|W. J. Hamilton]] |
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| | {{chicken}} |
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| | ==THE DEVELOPMENT OF THE CHICK - AN INTRODUCTION TO EMBRYOLOGY== |
| BY | | BY |
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| ==Part I The Early Development To The End Of The Third Day== | | ==Part I The Early Development To The End Of The Third Day== |
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| ==CHAPTER XIII THE URINOGENITAL SYSTEM== | | ==Appendix== |
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| The history of the pronephros and the origin of the mesonephros have been ah'eady described (Chap. VI). We have now
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| to consider (1) the later history of the mesonephros, (2) the
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| development of the metanephros or permanent kidney, (3) the
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| development of the reproductive organs and their ducts, and
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| (4) the development of the suprarenals. All these organs form
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| an embryological unit, by virtue of their mode of origin and their
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| interrelations. Thus we find that the intermediate cell-mass is
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| significant for the development of all: its growth causes the formation of the Wolffian body, on the median face of which the gonads
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| arise. The secreting tubules and renal corpuscles of the permanent kidney are also derivatives of the intermediate cell-mass.
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| The Wolffian duct is derived from the same source, and by change
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| of function becomes the vas deferens, after functioning for a while
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| as the excretory duct of the mesonephros. Certain parts of the
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| mesonephros also enter into the construction of the testis. And
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| the Miillerian duct, which forms the oviduct of the female, is
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| derived from the epithelium covering the Wolffian body.
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| I. The Later History of the Mesonephros
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| In Chapter VI we traced the origin of the nephrogenous
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| tissue, and the differentiation of the first mesonephric tubules
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| within it. We saw that in each of the segments concerned a
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| number of balls of cells arises by condensation within the nephrogenous tissue, and that these become converted into vesicles.
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| We saw also that each vesicle sends out a tubular sprout from
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| its lateral side to the Wolffian duct, with which it unites; and
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| that its median face becomes converted into a renal corpuscle.
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| These processes take place sucessively in antero-posterior order
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| within the somites concerned, so that a series of stages in the
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| development of the tubules may be studied in the same embryo.
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| Moreover, all the tubules of a given somite do not develop simul
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| .378
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| THE URIXOGEXITAL SYSTEM
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| 379
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| taneously: primary tubules are formed in each somite from the
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| most ventral portion of the nephrogenous tissue; then secondar}tubules later from an intermediate portion, and tertiary tubules
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| later yet from the dorsal portion.
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| Fig. 217 represents a transverse section through the middle
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| ^»f^^5^° v'"'it>f ^i:^j#^^'
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| Fig. 217. — Transverse section through the middle of the
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| Wolffian body of a chick embryo of 96 hours.
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| Ao., Aorta. Coel., Coelome. Col. T., Collecting tubule.
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| Glom., Glomerulus, germ. Ep., Germinal epithelium. M's't.,
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| Mesentery, n. t., Nephrogenous tissue. T. 1,2, 3, Primary,
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| secondary, and tertiary mesonephric tubules. V. c. p., Posterior cardinal vein. W. D., Wolffian duct.
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| of the Wolffian body at the stage of ninety-six hours, showing a
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| primary, secondary, and tertiary tubule. The primary tubule
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| is typically differentiated; the secondary has formed the secreting
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| tubule and the rudiment of the renal corpuscle, but the tubule
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| does not yet open into the Wolffian duct, though it is connected
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| with it; the tertiary tubule is still in the vesicular stage. Some
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| undifferentiated nephrogenous tissue remains above the rudiment of the tertiary tubule, which makes it possible that quarternarv tubules mav be formed later.
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| Referring still to the same figure, it will be noted that the
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| Wolffian duct itself has formed a considerable evagination dorsomedially (collecting tubule), with which both secondary and
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| tertiary tubules are associated as well as the undifferentiated
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| nephrogenous tissue. Similar evaginations are formed along
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| the entire length of the functional portion of the mesonephros.
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| 380
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| THE DEVELOPxAIEXT OF THE CHICK
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| 0(,
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| ov
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| o
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| Q>(
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| o
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| OO,
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| o
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| o
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| o
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| o r
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| o
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| xoz
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| X22
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| -2ZIC
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| 22YII
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| Fig. 114. A.
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| Figs. 218 and 219 illustrate the form of these evaginations in
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| duck embr3^os of 40 and 50 somites respectively, as they appear
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| in reconstructions of the posterior portion of the mesonephros.
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| It will be seen that they gradually
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| form sacs opening into the Wolffian
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| duct. Subsequently, by elongating,
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| these sacs form collecting tubules
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| that gather up the secretions of the
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| mesonephric tubules proper and conduct them to the Wolffian duct.
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| These conducting tubules are stated
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| to branch more or less; it is also
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| said that they are more highly developed in the duck than in the chick.
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| Felix proposes to call them mesonephric ureters.
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| In the case of the secondary and
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| tertiary tubules, three parts may be
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| distinguished : parts one and two (derived from the nephrogenous tissue)
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| I;. o\C ^rc the renal corpuscle and secreting
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| tubule respectively; the third part is
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| the collecting tubule derived by
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| evagination from the Wolffian duct.
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| In the case of the primary tubules,
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| a conducting part appears to be
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| formed secondarily, though in what
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| way is not clear.
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| The formation of new tubules
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| ceases on the fifth day, all the nephrogenous tissue being then used
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| up. Up to the eighth day at least
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| the tubules grow rapidly in length
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| and become more differentiated. The
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| result is a relatively enormous protrusion into the bodv-cavity on each
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| side of the dorsal mesentery. Degeneration of the tubules sets in
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| about the tenth or eleventh days,
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| and the tissue is gradually absorbed;
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| 2Mir
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| 'XSKT
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| THE URIXOGEXITAL SYSTEM
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| 381
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| this process extends over the whole of the latter period of incubation, and is completed at hatching. Parts, however, remain
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| in the male in connection with the testis; non-functional remnants
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| O ^ °o o
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| O
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| O.'l
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| ' ."fi.T •-.
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| yxxiii
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| n.T.
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| Fig. 219. — Profile reconstruction of part of the
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| mesonephros and diverticulum of the ureter of
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| a duck embryo of 50 somites. (After Schreiner.)
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| CI., Cloaca. Int., Intestine. Mn. T., Meso
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| nephric tubules, n. T., Nephrogenous tissue.
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|
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|
| Ur Ureter W. D.. Wolffian duct.
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|
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|
| XXXII, XXXIII, XXXIV, Somites of the
| | ===General Literature=== |
| same number.
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| may also be detected in the female (p. 401). It is difficult to
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| state the exact period of beginning and cessation of function of
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| the mesonephric tubules. Judging from the histological appear
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| PiG 918 — Profile reconstruction of part of the Wolffian duct and primordia
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| of mesonephric tubules (represented by circles) of a duck embryo of 45
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| somites. (After Schreiner.)
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| YXTV XXV etc., position of the correspondmg somites. Lines 114 A,
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| 114 B 114 C ^represent the positions of the sections shown in these figures.
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| 382
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| THE DEVELOPMENT OF THE CHICK
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| ances, however, it is probable that secretion begins in the tubules
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| on the fifth day and increases in amount up to the eleventh day
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| at least, when signs of degeneration become numerous. Presumably the functional activity diminishes from this stage on, being
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| replaced by the secretion of the permanent kidney.
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| SrC:^
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| Gq/?.-%
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| Fig. 220. — Transverse section through the mesonephros
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| and neighboring parts of a 6-day chick, in the region of
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| the spleen.
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| Ao., Aorta, bl. V., Blood vessels (sinusoids). Caps., Capsule of renal corpuscle. Coel., Coelome. col. T., Collecting
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| tubule. D., Dorsal. Giz., Gizzard. Glom., Glomerulus.
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| Gon., Gonad. L., Left. Spl., Spleen. Sr. C, Cortical substance of the suprarenal, s. t., Secreting tubule. T. R.,
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| Tubal rid^e. V., Ventral. V. c. p., Posterior cardinal vein
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| V. s'c. 1., Left subcardinal vein. W. D., Wolffian duct.
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| Figs. 220 and 221 represent sections through the mesonephros
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| on the sixth and eighth days respectively (see also Fig. 222,
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| eleven days). The renal corpuscles show the typical capsule
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| and glomerulus, and relation to the secreting tubules. The latter
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| are considerably convoluted on the sixth day, much more so on
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| the eighth day. The conducting tubules can usually be distinguished by their smaller caliber and thinner walls. The Wolffian
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| THE URIXOGEXITAL SYSTEM
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| 383
| |
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| duct is situated near the dorso-lateral edge of the mesonephros,
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| and the opening of a collecting tubule into it is shown in Figure
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| 220. The renal corpuscles are situated next the median face of
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| the Wolffian body. The space between the tubules is occupied
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| ';7.f.o.z.
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| Mh'tr
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| -3.?V
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| iVJ).
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| apmm
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| Gon.l
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| Fig. 221. — Transverse section through the metanephros, mesonephros,
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| gonads and neighboring parts of an 8-day chick,
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| bl. v., Blood vessels (sinusoids). B. W., Body-wall. col. T. M't'n.,
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| 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.
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| z., Outer zone of the nephrogenous tissue. Symp. Gn., Sympathetic o^anghon of the twenty-first spinal ganglion. V. C, Centrum of vertebra. Other
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| abbreviations as before.
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| almost entirely by a wide vascular network of sinusoidal character; that is, the endothelial walls of the vessels are moulded
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| directly on the basement membrane of the tubules without any
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| intervening connective tissue. The circulation is described in the
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| chapter on the vascular system.
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| 384 THE DEVELOPMENT OF THE CHICK
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| II. The Development of the Metaxephros or Permanent
| |
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| Kidney
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| The metanephros or permanent kidney supplants the mesonephros in the course of development. It is derived from two
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| distinct embryonic primordial (1) the nephrogenous tissue of
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| the two or three posterior somites of the trunk (31 or 32 to 33),
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| which furnish the material out of which the renal corjxiscles
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| and secreting tubules develop; and (2) a diverticulum of the
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| posterior portion of the Wolffian duct (Fig. 219), which develops
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| by branching into the collecting tubules and definitive ureter.
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| The development of the kidney takes place in a mass of mesenchyme, known as the outer zone of the metanephrogenous tissue,
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| that furnishes the capsule and connective tissue elements of
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| the definitive kidney, in which also the vascular supply is developed
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| (Figs. 221 and 222). The cortical tubules of the kidney are
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| thus derived mainly from the nephrogenous tissue, and the medullary tubules and ureter from the metanephric diverticulum.
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| Thus the definitive kidney is analogous in mode of development to the mesonephros, and is best interpreted as its serial
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| homologue. This point of view may be regarded as definitely
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| 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
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| and collecting tubules, arises about the end of the fourth da}^ as
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| a rather broad diverticulum of the Wolffian duct at the convexity
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| of its terminal bend to the cloaca (Fig. 219). It grows out
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| dorsally, forming a little sac, which, however, soon begins to grow
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| forward median to the posterior cardinal vein and dorsal to the
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| mesonephros (Fig. 224); by the end of the fifth day its anterior
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| 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
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| anterior end of the mesonephros (twenty-first definitive somite or
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| twenty-fifth of the entire series; cf. Fig. 150).
| |
| | |
| It should be noted that the metanephric diverticulum is similar
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| in its mode of origin to the so-called mesonephric ureters. It
| |
| may in fact be regarded as the posterior member of this series,
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| but it is separated from those that form the collecting tubules of
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| the mesonephros by at least two somites in which no diverticula
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| THE URINOGEXITAL SYSTEM
| |
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| 385
| |
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| of the mesonephros are formed (Fig. 219). During its growth
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| forward a series of small diverticula arise from its wall and extend
| |
| dorsally (Fig. 223); these branch secondarily in a generally dichot
| |
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| ,'-''^i,< ■•'>"!■'■-■<- ■■■■---■: .
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| Af^Y.
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| ^y^
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| 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.
| |
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| 386
| |
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| | |
| THE DEVELOPMENT OF THE CHICK
| |
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| Fig. 223. — Profile reconstruction of the Wolffian
| |
| duct and primordium of the metanephros of a
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| 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.,
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| Nephroojenous tissue of the metanephros included
| |
| within the dotted lines. W. D., Wolffian duct.
| |
| Ur., Ureter.
| |
| | |
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| | |
| 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
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| same, viz., that differentiation begins in the first formed parts.
| |
| | |
| (2) A posterior, smaller group of collecting tubules is separated
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| 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
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| into the cloaca independent of the Wolffian duct and posterior
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| 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
| |
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| 388
| |
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| THE DEVELOPMENT OF THE CHICK
| |
| | |
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| | |
| 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
| |
| | |
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| | |
| Fig. 224. — Transverse section through the
| |
| | |
| ureter and metanephrogenous tissue of a
| |
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| 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
| |
| | |
| | |
| | |
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| | |
| '1 •^^•^-'o.ool
| |
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| | |
| ^/7 — ^ ^ifflii'
| |
| | |
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| ^
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| .«"»
| |
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| | |
| , < r. ■,■
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| CdUd^C/ "^dl "■'5-S:^;
| |
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| /y7/i:/^
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| 7^^?l?
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| '»2g.' «>5.<' '• ^- .
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| | |
| .. °SS-,.
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| 1 vs^-i.^-"^'":^^^-^^
| |
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| 5 'D
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| o v.
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| 4^
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| ■^s
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| y;7/j. /--^ XtCf"^ -fi-.sV^ -o. o " :
| |
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| ■'-r-,'fc'-V' •'»'£'';'■■'/<' '?<^ Co"© ^ -^ .li-a - - S.Jo
| |
| | |
| | |
| | |
| ^ 6
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| ~ ^ Ask ' S»Jo - , ^»
| |
| | |
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| TK^r^
| |
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| . .0^:^
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| ^ «. . ', >^.-".,^e
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| «,,?rV.?:
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| ^!.
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| | |
| | |
| "-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*^-^-* -'.
| |
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| :^^V:. .
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| Mj/-"^^^
| |
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| | |
| ceph Sci.- ''^
| |
| | |
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| | |
| ^ \ . o c
| |
| | |
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| y^i-
| |
| | |
| | |
| .y.y^;{^^> -jt^.> " /^^.^
| |
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| | |
| 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/.
| |
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| caud Se/
| |
| | |
| s.A
| |
| cep/?.'5c/
| |
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| cac/f^ ^C/
| |
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| jtfy:
| |
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| i A^.V
| |
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| to ei\--^^ i-
| |
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| »",-^*
| |
| •c,-^
| |
| | |
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| | |
| >p.
| |
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| | |
| | |
| | |
| 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
| |
| | |
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| | |
| | |
| | |
| -^mk
| |
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| | |
| | |
| | |
| | |
| T/ltl
| |
| rceiMS.
| |
| | |
| | |
| | |
| , i: f 'j'f' , ., f , n yc
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| | |
| ■yj
| |
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| .-^,4^V^J^/?^.^^
| |
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| UJ:
| |
| | |
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| 5p.G/i2-Fi
| |
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| ^■>'i
| |
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| 'RVd.
| |
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| -+,-'
| |
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| '-■'oi-.S'"'- (,.'■>•,'■ I ■
| |
| | |
| | |
| | |
| 5i/mp.Cn
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| | |
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| -r/^V4
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| | |
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| | |
| 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).
| |
| | |
| | |
| | |
| | |
| | |
| | |
| | |
| | |
| | |
| | |
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| | |
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| | |
| 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 | | V. Baer, C. E., L'eber Entwickelurigsgeschichte der Tiere. Beobachtung |
Line 3,474: |
Line 57: |
| id., 2. Teil — Herausgegeben von Stieda. Konigsberg, 1888. | | id., 2. Teil — Herausgegeben von Stieda. Konigsberg, 1888. |
| Duval, Mathias, Atlas d'embryologie. (With 40 plates.) Paris, 1889. | | Duval, Mathias, Atlas d'embryologie. (With 40 plates.) Paris, 1889. |
| Foster, M., and Balfour, F. M., The Elements of Embryology. Second | | 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. |
|
| |
|
| Edition revised. London, 1883.
| |
| Gadow, Hans, Die Vogel, Bronn's Klassen und Ordniingen des Thier-Reichs,
| |
|
| |
|
| Bd. VI, Abth. 4, 1898.
| | Hls, W., LTntersuchungen fiber die erste Anlage des Wirbeltierleibes. Die erste Entwickelung des Hiihnchens im Ei. Leipzig, 1868. |
| Handbuch der vergleichenden und experimentellen Entwickelimgslehre der
| | Keibel, F., and Abraham, K., Normaltafeln zur Entwickelungsgeschichte des Huhnes (Gallus domesticus). Jena, 1900. |
|
| |
|
| 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 | | V. KoLLiKER, A., Entwickelungsgeschichte des Menschen und der hoheren |
|
| |
|
Line 3,508: |
Line 83: |
| Remak, R., Untersuchungen iiber die Entwickelung der Wirbelthiere. Berlin, 1855. | | Remak, R., Untersuchungen iiber die Entwickelung der Wirbelthiere. Berlin, 1855. |
|
| |
|
| LITERATURE — CHAPTER I
| | ===Literature — Chapter I=== |
|
| |
|
| Bartelmez, George W., 1912, The Bilaterality of the Pigeon's Egg. A | | Bartelmez, George W., 1912, The Bilaterality of the Pigeon's Egg. A |
Line 3,544: |
Line 119: |
|
| |
|
| of the Oviduct. Journ. of Exp. Zoology. Vol. 12, pp. 99-132. | | of the Oviduct. Journ. of Exp. Zoology. Vol. 12, pp. 99-132. |
| Riddle, Oscar, 1911, On the Formation, Significance and Chemistry of | | 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. |
|
| |
|
| the White and Yellow Yolk of Ova. Journ. of Morph., Vol. 22, pp.
| |
|
| |
| 455-490.
| |
| SoNNENBRODT, 1908, Die Wachstunsperiode der Oocyte des Huhns. Arch. | | SoNNENBRODT, 1908, Die Wachstunsperiode der Oocyte des Huhns. Arch. |
|
| |
|
Line 3,556: |
Line 128: |
| Entwickelungslehre der \Yirbeltiere. Bd. I, T. 1, 1901. | | Entwickelungslehre der \Yirbeltiere. Bd. I, T. 1, 1901. |
|
| |
|
| LITERATURE — CHAPTER II
| | ===Literature — Chapter II=== |
|
| |
|
| Andrews, E. A., Some Intercellular Connections in an Egg of a Fowl. The | | Andrews, E. A., Some Intercellular Connections in an Egg of a Fowl. The |
Line 3,593: |
Line 165: |
| XXII, 1872. | | XXII, 1872. |
|
| |
|
|
| |
|
| |
| APPENDIX 445
| |
|
| |
|
| Patterson, J. Thomas, Gastrulation in the Pigeon's Egg; a ^Morphological | | Patterson, J. Thomas, Gastrulation in the Pigeon's Egg; a ^Morphological |
Line 3,614: |
Line 183: |
| Anat. u. Entwickelungsgesch., Bd. V, 1895. | | Anat. u. Entwickelungsgesch., Bd. V, 1895. |
|
| |
|
| LITERATURE — CHAPTER III
| | ===Literature — Chapter III=== |
|
| |
|
| Edwards, C. L., The Physiological Zero and the Index of Development for | | Edwards, C. L., The Physiological Zero and the Index of Development for |
Line 3,632: |
Line 201: |
| 1894. | | 1894. |
|
| |
|
| LITERATURE — CHAPTERS IV AND V
| | ===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. | | Assheton, R., An Experimental Examination into the Growth of the Blastoderm of the Chick. Proc. Roy. Soc, London, Vol. LX, 1896. |
Line 3,669: |
Line 239: |
| 1879. | | 1879. |
|
| |
|
|
| |
|
| |
| 446 APPENDIX
| |
|
| |
|
| Gasser, Beitrage zur Kenntnis der Vogelkeimscheibe. Arch. Anat. u | | Gasser, Beitrage zur Kenntnis der Vogelkeimscheibe. Arch. Anat. u |
Line 3,748: |
Line 315: |
|
| |
|
|
| |
|
|
| |
| APPENDIX 447
| |
|
| |
|
| Peebles, Florence, The Location of the Chick Embryo upon the Blastoderm. Journ. Exp. Zool., Vol. I, 1904. | | Peebles, Florence, The Location of the Chick Embryo upon the Blastoderm. Journ. Exp. Zool., Vol. I, 1904. |
Line 3,768: |
Line 333: |
| Ueber die erste Entwickelung der Vogel und die Bedeutung der Primi | | Ueber die erste Entwickelung der Vogel und die Bedeutung der Primi |
| tivrinne. Sitz.-ber. d. naturf. Ges. zu Leipzig, 1876. | | tivrinne. Sitz.-ber. d. naturf. Ges. zu Leipzig, 1876. |
| Rex, Hugo, Ueber das Mesoderm des Vorderkopfes der Ente. Archiv. | | Rex, Hugo, Ueber das Mesoderm des Vorderkopfes der Ente. Archiv. mikr. Anat., Bd. L., 1897. |
| | |
|
| |
|
| ■ mikr. Anat., Bd. L., 1897.
| |
| RiiCKERT, J., Entwickelung der extra-embryonalen Gefasse der Vogel. Hand | | RiiCKERT, J., Entwickelung der extra-embryonalen Gefasse der Vogel. Hand |
| buch der vergl. w. exp. Entw.-lehre der Wirbelthiere, Bd. I, T. 1, | | buch der vergl. w. exp. Entw.-lehre der Wirbelthiere, Bd. I, T. 1, |
Line 3,808: |
Line 373: |
| Literature to Chapter VI included in following chapters. | | Literature to Chapter VI included in following chapters. |
|
| |
|
| LITERATURE — CHAPTER VII
| | ===Literature — Chapter VII=== |
| | |
|
| |
|
| CHARBONNEiy-SALLE ct Phisalix, De I'evolution postembryonnaire du | | CHARBONNEiy-SALLE ct Phisalix, De I'evolution postembryonnaire du |
Line 3,823: |
Line 389: |
| Paris, 1877. | | Paris, 1877. |
|
| |
|
|
| |
|
| |
| 448 APPENDIX
| |
|
| |
|
| Duval, M., Sur ime organe placentoide chez rembryon des oiseaux. C. R. | | Duval, M., Sur ime organe placentoide chez rembryon des oiseaux. C. R. |
Line 3,898: |
Line 461: |
| im Bereiche des Dottersackes. Virchow's Arch., Bd. LXII, 1874. | | im Bereiche des Dottersackes. Virchow's Arch., Bd. LXII, 1874. |
|
| |
|
|
| |
|
| |
| APPENDIX 449
| |
|
| |
|
| ViRCHOW, H., Ueber das Epithel des Dottersackes im Hiihnerei. Diss., Berlin. | | ViRCHOW, H., Ueber das Epithel des Dottersackes im Hiihnerei. Diss., Berlin. |
Line 3,921: |
Line 481: |
| Weldox, W. F. R., Prof, de Vries on the Origin of Species. (Includes experiments on amnion.) Biometrica, Vol. I, 1902. | | Weldox, W. F. R., Prof, de Vries on the Origin of Species. (Includes experiments on amnion.) Biometrica, Vol. I, 1902. |
|
| |
|
| LITERATURE — CHAPTER VIII
| | ===Literature — Chapter VIII=== |
|
| |
|
| Beard, J., Morphological Studies, II. The Development of the Peripheral | | Beard, J., Morphological Studies, II. The Development of the Peripheral |
Line 3,972: |
Line 532: |
|
| |
|
|
| |
|
|
| |
| 450 APPENDIX
| |
|
| |
|
| Heinrich, Georg, Untersuchungen iiber die Anlage des Grosshirns beim | | Heinrich, Georg, Untersuchungen iiber die Anlage des Grosshirns beim |
Line 4,029: |
Line 587: |
| Zool. Anz., Bd. IX, 1886. | | Zool. Anz., Bd. IX, 1886. |
|
| |
|
| LITERATURE — CHAPTER IX
| | ===Literature — Chapter IX=== |
| | |
| Organs of Special Sense | | Organs of Special Sense |
|
| |
|
Line 4,037: |
Line 596: |
| 1901-1902. | | 1901-1902. |
|
| |
|
|
| |
|
| |
| APPENDIX 451
| |
|
| |
|
| AddariOjC, Ueber die Matrix desGlaskorpers im menschlichen und thierischen | | AddariOjC, Ueber die Matrix desGlaskorpers im menschlichen und thierischen |
Line 4,118: |
Line 674: |
|
| |
|
|
| |
|
|
| |
| 452 APPENDIX
| |
|
| |
|
| NussBAUM, M., Die Pars ciliaris retinae des Vogelauges. Arch. mikr. Anat., Bd. | | NussBAUM, M., Die Pars ciliaris retinae des Vogelauges. Arch. mikr. Anat., Bd. |
Line 4,195: |
Line 749: |
| in der Reihe der Wirbeltiere. Bildung der ausseren Nase und des | | in der Reihe der Wirbeltiere. Bildung der ausseren Nase und des |
|
| |
|
|
| |
|
| |
| APPENDIX 453
| |
|
| |
|
| Gaumens. Handbuch der vergl, und experiment. Entwickelimgslehre | | Gaumens. Handbuch der vergl, und experiment. Entwickelimgslehre |
Line 4,247: |
Line 798: |
| Sitzungsber. Akad. Miinchen, 1888. | | Sitzungsber. Akad. Miinchen, 1888. |
|
| |
|
| LITERATURE — CHAPTER X
| | ===Literature — Chapter X=== |
| | |
| The Alimentary Tract and Its Appendages | | The Alimentary Tract and Its Appendages |
|
| |
|
Line 4,264: |
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 |
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.
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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.
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Der Parablast unci der Keimwall der Vogelkeimscheibe. Sitz.-Ber.
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GoETTE, A., Beitrage zur Entwickelungsgeschichte der Wirbeltiere. II.
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Hertwig, O., Die Lehre von den Keimblattern. Handbuch der vergl. und
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His, W., Der Keimwall des Htihnereies und die Entstehung der para
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Neue Untersuchung liber die Bildung des Hiihnerembryo. Arch.
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Hubbard, M. E., Some Experiments on the Order of Succession of the
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Janosik, J., Beitrag zur Kenntnis des Keimwulstes bei Vogeln. Sitz-Ber
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Rauber, a., Primitivstreifen und Neurula der Wirbelthiere, in normaler
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RiiCKERT, J., Entwickelung der extra-embryonalen Gefasse der Vogel. Hand
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ScHAUiNSLAND, H., Bcitrage zur Biologie und Entwickelung der Hatteria
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Literature to Chapter VI included in following chapters.
Literature — Chapter VII
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Literature — Chapter VIII
Beard, J., Morphological Studies, II. The Development of the Peripheral
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A quelle epoque aparaissent les expansions des cellules nerveuses de
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Froriep, a., Ueber Anlagen von Sinnesorganen am Facialis, Glossopha
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Literature — Chapter IX
Organs of Special Sense
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Rabl, C, Ziir Frage nach der Entwickehmg des Glaskorpers. Anat. Anz.,
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B. The Nose
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Zur Entwickekmg der Gehorblase bei den WirbeUieren. Arch. mikr.
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Retzius, G., Das Gehororgan der Wirbelthiere. II. Theil, Reptihen Vogel,
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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
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GiACOMiNi, E., Sulle glanduH sakvari degk uccelk. Richerche anatomico
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GoppERT, E., Die Bedeutimg der Zunge ftir den secundaren Gaumen und den
Ductus naso-pharyngeus. Beobachtungen an Reptilien und Vogeln.
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Kallius, E., Die mediane Thyreoideaanlage und ihre Beziehung zum Tuber
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Beitrage zur Entwickelung der Zunge. Verb. anat. Ges., 15. Vers.
Bonn, 1901.
Manno, Andrea, Sopra il niodo onde si perfora e scompare le membrana
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IX, 1902.
Oppel, a., Lehrbuch der vergleichenden mikroskopischen Anat. der Wir
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Reichel, p., Beitrag zur Morphologie der ^Mundhohlendriisen der Wirbel
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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.
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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.
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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.
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Seessel, a., Zur Entwickelungsgeschichte des Vorderdarms. Arch. Anat.
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Verdun, M. P., Sur les derives branchiaux du poulet. Comptes rendus
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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
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Cazin, M., Recherches anatomiques, histologiques et embryologiques sur
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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
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Cloetta, M., Beit rage zur mikroskopischen Anatomic des Vogeldarmes.
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Fleischmaxx, Albert, Morphologische studien uber Kloake und Phallus der
Amnioten. III. Die Vogel, von Dr. Carl Pomayer. Morph. Jahrb.,
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Gasser, E., Beitrage zur Entwiekelungsgeschichte der Allantois, Miiller
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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.
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Geschlechtsapparates der Amnioten. Internat. Monatschr. Anat. u.
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Pomayer, Carl. See Fleischmann.
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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.
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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.
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Norsa, E., Alcune richerche sulla morphologia dei membri anteriori degli
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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.
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1850-1855.
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Anat. Anz., Bd. IV, 1889, and V, 1890.
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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