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| [[file:Mark_Hill.jpg|90px|left]] This historic 1909 paper by Thyng describes the development of the pancreas in several different species, including man.

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=Models of the Pancreas in Embryos of the Pig, Rabbit, Cat, and Man=

By

Fred W. Thyng, Ph. D (1908)

From the Department of Comparative Anatomy, Harvard Medical School.

This investigation has been aided by a Bullard Fellowship, established in memory of John Ware.

With 6 Text figures.

==Introduction==
The pancreas of mammals is now generally described as arising in the embryo from a dorsal pancreas, and a ventral pancreas, the latter often being subdivided into a right and a left part. Each embryonic portion has its own duct. The duct of the ventral pancreas has been known as the duct of Wirsung, for which term the Basle nomenclature substitutes “pancreatic duct” (''ductus pancreaticus''). The duct of the dorsal pancreas, formerly known as the duct of Santorini, which becomes secondary or disappears in man, is called the “accessory pancreatic duct” (''ductus pancreaticus accessorius''). The elimination of personal names is desirable, but the terms substituted may be criticised as applicable only to man. The duct of the dorsal pancreas which alone persists in the pig cannot properly be called either the pancreatic or the accessory pancreatic duct.


Appreciating this difficulty, Revell, 02, proposed the terms ductus hepatopancreatis sea dorsopancreatis, and dactus ventropancreatis. The compound terms here introduced are contrary to the principles of the Basle nomenclature and are not in good Latin form. The following terms avoid these difficulties; they accord with the Basle system, and can be used both in human and comparative anatomy.


{|
! width=300px|Latin
! width=300px|English
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| Ductus pancreatis dorsalis
| Duct of the dorsal pancreas
|-
| Ductus pancreatis ventralis
| Duct of the ventral pancreas
|}



These terms will be used in the following pages. Where no emphasis upon morphological or embryological relations is desired, the name pancreatic duct is often suificient.

==Pig Embryos==

Wlassow, 95, was the first to describe the development of the pancreas in the pig. I-Ie figures a model and transverse sections of the pancreas in an 8.”/—mm. pig, and also describes with the aid of transverse sections a still younger embryo (8 mm).

Vélker, 02, describes the development of the pancreas of the pig, from a series of models in the embryological collection of the University in Prague. He pictures three of these in figs. 19, 20, and 21, but unfortunately does not give either the age or length of the embryos from which the models were made.

Lewis, 03, reconstructed a l2—mm. pig embryo, and in Plate III shows incidentally the gross relations of the pancreas.

 

'''Fig. 1.''' Reconstruction from a pig embryo of 5.5 mm. (H. E. C. 915). X 55 diams. a, I), C, d, cords of hepatic cells. Pcmc. d., pancreas dorsale. Pane. 1)., pancreas ventrale. S1/‘., stomach. Ves. fel., vesica. fellea. ac, ventral process of the dorsal pancreas, on the right of the portal vein.

The first model which I shall describe is from a pig embryo 5.5 mm. in length (I-Iarvard Embryological Collect-ion, Series 915). In fig. 1 it is drawn from the right side, as are the models of Wlassow and Volker.


A little beyond the stomach (St) the hepatic diverticulum opens into the ventral side of the duodenum. Distally it presents a considerable enlargement from which project several cords of hepatic cells (a, b, c, d, etc.), one of which will ultimately form the hepatic duct. The gall bladder (Vcs. fel.) at this stage is represented by a distinct pouch from the distal, posterior or caudal wall of the diverticulum. Another out— growth from the posterior wall of the diverticulum is found near its intestinal orifice; this is the ventral pancreas (Pane. 12.). It is a ﬂattened triangular struc-ture attached to the hepatic divcrticulum by a stalk which has no lumen. The expanded basal portion of the triangle, situated in the ventral mesentery, extends laterally to both sides, but chieﬂy to the right in an obliquely dorsal direction. It is closely applied to the ventral wall of the right vitelline vein, wall of the duodenum, a little beyond the duct of the dorsal pancreas, and in line with it. Thus it is a dorsal structure. Where the duct of the accessory pancreas passes through the intestinal musculature it is somewhat constricted, suggesting that eventually it might become separated from the intestinal epithelium. This outgrowth has a distinct lumen and is somewhat expanded at its distal extremity where the cells are of the same nature as those in the other portions of the pancreas. So far as known such an accessory pancreas in an embryo has not been figured previously. This diverticulum and the small “accessory pancreas” pictured by Volker (p. 86, fig. 21) will be discussed in the following paper.


The dorsal pancreas (Pcmc. d.) is an outgrowth from the dorsal Wall of the intestine nearly opposite the orifice of the hepatic diverticulum. It is already of greater dimensions than the Ventral pancreas. It extends dorsally in the great omentum, and sends a subdivision  to the right and ventrally, reaching‘ the dorsal wall of the Vitelline Vein. The Vein is thus being encircled on its right side by the two parts of the developing pancreas (Prmc. cl. and 12.).



'''Fig. 2.''' Reconstruction from a pig embryo of 20 mm. (H. E. C. 60). ><55 diarns. Dim, duodenal diverticulum. D. chol., ductus choledochus. D. pane. d., ductus pancreatis dorsalis. D. pane. 22., ductus pancreatis ventralis. Pane. acc., pancreas accessorium. Pane. d., pancreas dorsale. Pane. 21., pancreas ventrale. St, stomach. ac, ventral process of the dorsal pancreas. on the right of the portal vein.


Another unusual condition of the pancreas was found in a 12-mm. pig embryo where a process of the ventral pancreas extended to the left, passing around the ventral side of the duodenum and nearly reaching the dorsal pancreas ; thus the duodenum was surrounded for more than threefourths of its circumference by pancreatic tissue. This condition suggests how a ring of pancreas surrounding the intestine may develop embryologically. Although I am not aware that such a ring has ever been found in the adult pig, Ecker, 62, observed a case in man where the head of the pancreas completely encircled the descending part of the duodenum. This is a rare occurrence. Apparently only one other similar case has been observed (Symington, 85).

==Rabbit Embryos==

Hammar, 93, in his Work upon the development of the liver incidentally figured the condition of theypancreas, as found in rabbit embryos of 3 mm. (10 days), 4.5 mm'.,'5 mm. (11 days), and 8 mm. (fig. 1, 2, 3, u. 4, Taf. XI); and in a later paper, 97, he adds a figure of the pancreas of a rabbit of 10 mm.

Joubin, 95, describes the pancreas as found in rabbit embryos of 13, 14, 15, 18, and 21 days.

Brachet, 96, has modeled and described the pancreas in embryos of 104;, 11-}, 12.13, and 13?; days (Plate XVIII, figs. 4, 5-6, 7, and 8).

Helly, or, has modeled the pancreas in embryos of 3.8, 4.8, 5.4, and 7 mm. (fig. 1-2, 4, 5, u. 6, Taf. XV). He also investigated embryos of 79; mm., 8 mm., and 3% cm. His conclusions agree essentially with those of Brachet.


The model which I shall describe is from a rabbit embryo of 14 days (11 mm.). It shows a more advanced condition of the embryonic pancreas than has been modeled heretofore in the rabbit. In the drawing (fig. 4) theimodel is viewed somewhat ventral.l.y from the right side. The stomach (St.) has revolved to the left, so that the pylorus extends towards the right side of the embryo. The duodenum extends from the  pylorus transversely across the median line to the right, then descends for a long distance on the right side of the portal vein, ventral to the right Woltfian body. It then turns back on the median side of its deseending course. Slightly to the right of the median line at the top of the long clcscending branch of the duodenum, the bile duct (D. 07101.) joins the intestine. Entering the bile duct quite close to its intestinal orifice, we see the duct of the ventral pancreas (D. pane. 12.). By comparing figs. 2 and 3 we see that essentially the same process of development has occurred in the rabbit as in the pig. Simultaneously with the formation of the duodenal loop, the opening of the duct of the dorsal pancreas (D. pane. d.) has been. carried a long distance beyond the opening of the common bile duct.

 


'''Fig. 3.''' Reconstruction from a rabbit embryo of 14 days, 11 mm. (H. E. C. 327). X 55 diams. The lettering is the same as in fig. 2.


The ventral pancreas (Paine. 12.) extends across the proximal part of the dorsal pancreas (Pane. (1.), the two having anastomosed at the place of crossing. From the investigations of Schiriner, 93, and Joubin, 95, it would appear that an anastomosis at this place does not occur invari


Vein. Its duct (D. prmc. 1'.) extends through the Ventral mesentery to enter the bile duct near its intestinal orifice.

The dorsal pancreas (Pane. d.) ventral to the portal vein, lies in the dorsal mesentery and extends through it into the mesogastrium. Its duct (D. pcmc. cl.) passes through the dorsal mesentery to enter the duodenum a little beyond the common bile duct. The dorsal pancreas has developed a short process (:22) which we can compare with the subdivision :2: in the pig (fig. 2). That such a process develops in the cat we know from the description and figures of Heuer, 06. He says (p. 107) :

 

'''Fig. 4.''' Reconstruction from a cat embryo of 10.7 mm. (H. E. C. 474). X 55 diams. The lettering is the same as in fig. 2.


Lying in the plica duodenojejunalis between the caput and cauda is a narrow strip of glandular tissue, the shape of which varies considerably. It is characteristic in the cat, having been found in every adult examined. It occurs in two forms, either as a bridge connecting the caput and cauda, or as an arm or spur, that is an outgrowth from the caput or cauda, but not joining the two limbs. The former type is by far the most frequent. Of 35 cases examined, the bridge type was presented in 25, the arm or spur type in four, an incomplete formation in five, while in one case, a young animal, it was lacking altogether.


Gage, 78, Schirmer, 93, and Heuer, 06, have shown that both ducts normally exist in the adult, and have the same relation as found in the ernbryo,—the duct of the dorsal pancreas enters the intestine beyond the orifice of the common bile duct.


==Human Embryos==

The pancreas was first studied in man. Wirsung, 1642-43, is considered the discoverer of the duct which opens into the intestine by Way of the bile duct.

Vesling, 1664, De Graaf, 167i, and several other investigators Of that time, noted the occasional presence of a second pancreatic duct which they considered abnormal.

Santorini, 1775, and Bernard, 56, believed in the normal presence of two pancreatic ducts.

In 85, His published reconstructions of human embryos, showing the dorsal but not the ventral pancreas.

Phisalix, 88, was the first to explain embryologically the presence of two pancreatic ducts. In a human embryo of 10 mm., he found that the pancreas developed from two separate parts. One part corresponded with the “ conduit accessoire,” and developed from the duodenum a little above the common bile duct. The other, of smaller dimensions, corresponded with the “canal de Wirsung,” and was in intimate relations with the bile duct.


Zimmermann, 89, investigated a human embryo of 7 mm., and described a double ventral pancreas, arising from the bile duct.


Felix, 92, figured the pancreas in a human embryo of 8 mm. (fig. 18, Taf. XVII). He pictures a dorsal pancreas arising from the intestine anterior to the bile duct. The ventral pancreas is double, the left part being rudimentary.


Hamburger, 92, figures models of the pancreas in human embryos of five and six weeks (fig. 2 u. 3). In both, the duct of the dorsal pancreas enters the intestine nearer the stomach than the bile duct. Hamburger found, in an embryo of four weeks, that the ventral pancreas arose from the intestinal wall some distance below the bile duct. He concluded, therefore, that it secondarily became connected with the latter.


Janosik, 95, represents in figs. 18 and 20 the pancreas in human embryos of 1 and 2.9 cm. In the younger embryo the opening of the common bile duct is nearer the stomach than that of the dorsal pancreas. In the older embryo the relation is reversed.


Jankelowitz, 95, studied the pancreas in a human embryo of 4.9 mm., and describes a dorsal and a ventral pancreas, the latter composed of right and left divisions.


Swaen, 97, described the pancreas as found in embryos of 10 mm., 18 mm., 15 mm. (nuchal length), and 4.5 cm. His model of the pancreas of the 10-mm. embryo (figs. XI a.nd XII, Pl. I) agrees essentially with those of Hamburger. The dorsal pancreas at this stage was separate from the ventral, but in the 18-min. embryo anastomosis between the two had occurred ventral to the portal vein.


Helly, or, figures the pancreas of a 11-mm. human embryo (fig. 30, Taf. XVII). He represents the dorsal pancreas as arising from the intestine nearer the pylorus than the opening of the bile duct. He also represents a right and a left ventral pancreas arising from the common bile duct. The ‘right ventral pancreas is the larger; the left shows evidence of degeneration. In a later publication, 04, he cites two cases (human embryos of 6.5 and 9.5 mm.) where the dorsal pancreas has a pronounced cranial position. Helly believes that in man the final position of the opening of both pancreatic ducts is established at the very beginning of their development.
 



'''Fig. 5.''' Reconstruction from a human embryo or 7.5 mm. (H. E. C. 256). X 55 diams. D. choZ., ductus choledochus. D. cyst, ductus cysticus. D. hep.. ductus hepaticus. Pcmc. d., pancreas dorsale. Pcmc. 17., pancreas ventrale. St., stomach. Ves. feZ., vesica fellea.



Volker, 02, describes two human embryos, one of 3 mm., the other of 13 mm. In the younger embryo the dorsal pancreas is an outpocketing from the dorsal wall of the duodenum. The greater part of it is posterior to the liver. In the older embryo (13 mm.) the duct of the dorsal pancreas opens into the dorsal side of the intestine at about the same level as the common bile duct. In this paper and in a later publication, 03, Volker maintains that the bile and pancreatic ducts are not developed at first in their final relation to one another, but that in the course of embryonic development they move in opposite directions, and that in this way their primary relations may be reversed.


Kollmann, 07, shows three original pictures of the pancreas as found in human embryos of 7.5 mm., 5 and 6 weeks (fig. 39%, 395, u. 397). In each of the three embryos the duct of the dorsal pancreas, “ ductus pan creaticus secundarius,” enters the intestine nearer the stomach than the common bile duct.


[[File:Thyng1908 fig06.jpg|600px|alt=Pancreas reconstruction from a human embryo of 13.6 mm]]

'''Fig. 6.''' Reconstruction from a human embryo of 13.6 mm. (H. E. C. 839). X 55 diams.D. chol., ductus choledochus. D. cyst., ductus cysticus. D. hep., ductus hepaticus. D. panc. d., ductus pancreatis dorsalis. D. panc. v., ductus  pancreatis ventralis. Panc. d., pancreas dorsale. Panc. d., pancreas ventrale. St., stomach.

Ingalls, 07, figures a model of a pancreas in a 4.9 mm. human embryo (fig. 3 u. 4, Tat.  He describes a dorsal pancreas and agrees with Jankelowitz that the ventral pancreas shows its double origin, “ yet there is only a suggestion of the paired condition.” _ Models of the human pancreas are shown in figs. 5 and 6. fig. 5 is from a human embryo of 7.5 mm.  E. O. 256). The dorsal pancreas (Panic. d.) arises from the dorsal wall of the duodenum a little nearer the stomach (St) than the bile duct (D. 07102.), the posterior border of the pancreas being approximately on a level with the anterior wall of the bile duct. This pancreatic outgrowth extends into the dorsal mesentery. A little posterior to the duct of the dorsal pancreas, the common bile duct (17. chol.) opens into the ventral side of the intestine. It terminates distally in the hepatic and cystic ducts (D. hep. and D". cyst), the latter passing to the ventrally placed gall bladder (Ves. fel.). The ventral-pancreas (Pane. v.) is a small solid mass of cells arising from the posterior Wall of the common bile duct, close to its union with the intestine. It extends posteriorly and a little to the right, but is still considerably removed from the ventral border of the portal vein.


The second model (fig. 6) is from an embryo of 13.6 mm. (H. E. C. 839). It is evident that this is a much more advanced condition _than that just described. The model is here represented, somewhat ventrally, from the right side. The stomach (St) has so revolved that its primitive dorsal border or greater curvature is now toward the left, and its ventral border or lesser curvature toward the right.


The dorsal pancreas (Pane. d.) is very large as compared with the ventral pancreas (Pomc. z=.). Its duct (D. pcmc. cl.) opens into the duodenum nearer the stomach than the bile duct (D. ch0l.), as was shown in the younger embryo. Distally it extends into the mesogastrium. There is, however, no process encircling the right side of the portal vein such as was found in the pig and rabbit embryos, the condition being more like that in the eat of 10.7 mm.


The ventral pancreas (Pcmc. 1).), which in the drawing is more darkly shaded than the dorsal pancreas, forms only a very small part of the pancreatic tissue. By the growth of the duodenum the ventral pancreas has been carried into close relation with the proximal part of the dorsal pancreas as happened in the pig embryo (fig. 2). The two parts of the pancreas (Pomc. d. and 11.) already anastomose ventral to the portal vein and on the left of the common bile duct.


The duct of the ventral pancreas (D. pane. 1).) is well developed at this stage, and according to Hamburger, 92, Schirmer, 93, Joubin, 95. Oharpy, 98, Helly, 98, Opie, 03, and Baldwin, 07, its absence is exceptional in the human adult. Thus these investigators confirm the earlier opinion of Santorini and Bernard.


The human pancreatic ducts differ from those of other mammals studied in that usually the duct of the dorsal pancreas opens into the intestine, nearer the stomach than the common bile duct; in other mammals the duct of the dorsal pancreas is beyond the bile duct. Even in young human embryos the dorsal pancreas is distinctly anterior to the intestinal orifice of the bile duct (fig. 5; Felix, fig. 18, Taf. XVII; Helly, fig. 30, Taf. XVII; Kollmann, fig. 394; Ingalls, fig. 3 u. -’l, Tat‘. XXX; etc.). Several cases, however, are recorded both in the embryo (His, 85, Wlassow, 94, J'anosik, 95, Volker, 02 and 03, et al.), and in the adult (Owen, 68, and others) where the duct of the dorsal pancreas opens into the intestine beyond the opening of the common bile duct. These cases, however, must be exceptions to the normal condition. My evidence for this conclusion is derived from a study of these ducts in the following series of eighteen human embryos in the Harvard Em.bryological Collection: 256 (7.5 mm.), 81'? (8 mm.), 529 (9.4 mm.), 1005 (9.4 mm.), 1001 (9.6 mm.), 1000 (10 mm.), 736 (10.2 mm.), 816 (12 'mm.), 839 (13.6 mm.), 1003 (14.5 mm.), 1128 (16 mm.), 1129 (18.1 mm.), 819 (19 mm.), 828 (19 mm.), 851 (22 mm.), 8"/1 (22.8 mm.), 181 (23 mm.), and 38 (24 mm.). In. every one of these embryos the duct of the dorsal pancreas was found to be nearer the stomach than the intestinal opening of the common bile duct.

==Summary==

From the preceding study it is seen that in the pig, rabbit, cat, and man, there is a dorsal and a ventral pancreas. In the eighteen human embryos examined the dorsal pancreas arises from the intestine distinctly anterior to the hepatic diverticulum, and in the human adult its duct is generally found to be nearer the stomach than the orifice of the bile duct. In the pig, rabbit, and cat, the duct of the dorsal pancreas opens into the duodenum beyond the bile duct.


In the rabbit and the pig the dorsal pancreas shows, very early in its development, distinct right and left lobes spreading from a common stem; such lobes were not found in human embryos. The ventral pancreas is often described as arising from independent right and left halves, of which the left very soon disappears. The present study has shown no sufficient reason for subdividing the ventral pancreas into two independent lateral parts.


The dorsal pancreas sends a ventral process on the right side of the right vitelline vein, to fuse with the ventral pancreas. This process i.s well developed in the pig and rabbit. In the eat of 10.7 mm. it is indicated, and in the adult cat it is sometimes present and sometimes absent (Heuer). In the human embryo it did not occur, and in the pancreas of the human adult its existence has apparently not been recorded.


By the development of the duodenal loop and associated with the rotation of the stomach, the dorsal pancreas is brought into contact with the ventral pancreas at a second point. Here, on the ventral side of the portal vein, the two anastomose. In those cases in which the ventml p2'0ca.ss has fused with the ventral pancreas, a ring of pancreatic tissue surrounding the portal vein is thus completed. The perivenous ring is absent in man, occasional in the cat, and characteristically present in the rabbit and pig.


==Literature Cited==

BALDWIN, W. M.—The Ductus Pancreaticus Accessorius in Man. Anatomical Record, Vol. I, p. 66, 1907.

BERNARD, CLAUoE.—Mé-moire sur le pancreas. Supplement aux compt. rend. Acad. des Sciences, Paris. Tome I, 1856.

BRACHET, A.—-Recherches sur le développement du pancreas et du foie (Sélaciens, Reptiles, Mammiferes). Journ. de l’Anat. et de la Physiol., pp. 620-696, Pls. XVIII-XX, 1896.

CI-IARPY, A.—Variétés et anomalies des canaux pancréatiques. Journ. de 1’Anat. et de la Phys., pp. 720-734, 1898.

DE GRAAF, R.—Tractatus Anat. Med., 1671.

ECKER, A.—Bildungsfeh1er des Pankreas und des I-Ierzens. Zeitschr. 5:‘. mt. Med. 3. R. Bd. XIV, S. 354-356, Taf. VI, 1862.

FELIX, W.—Zur Leber und Pankreasentwickelung. Arch. 1:‘. Anat. u. Phys, Anat. Abthlg., S. 281-323, Taf. XVI-XVIII. 1892.

GAGE, S. H.—The Ampulla of Vater and the Pancreatic Ducts in the Domestic Cat. Amer. Quart. Micr. Journ., Vol. I, pp. 1-20, Pls. XII—XIV, 1878.

HAMBURGEE.—Zur Entwickelung der Bauchspeicheldriise des Menschen. Anat. Anz., Bd. VII, S. 707-711, 1892.

HAMMAR, J. A.—Einige Plattenrnodelle zur Beleuchtung der friiheren embryonalen Leberentwickelung. Arch. f. Anat. u. Phys., Anat. Abthlg., S. 123-156, Taf. XI u. XII. 1893.

: Ueber einige I-Iauptziige der ersten embryonalen Leberentwickelung. Anat. Anz., Bd. XIII, S. 233-247, 1897.

HELLY, K.—Beitr':lge zur Anatomie des Pankreas und seiner Ausfiihrungsgange. Arch. f. mikr. Ana.t., Bd. LII, S. 773-793, Taf. XXXIII u. XXXIV, 1898.

Zur Pankreasentwickelung der Séiugethiere. Arch. f. mikr. Anat. u. Entwick1ungsgesch., Bd. LVII, S. 271-335, Taf. XV, XVI u. XVII, 1901.

Zur Frage der priméren Lagebeziehungen bei der Pankreasanlagen des Menschen. Arch. f. mikr. Anat., Bd. LXIII, S. 631-635, 1904.

HEUER, G. J.—The Pancreatic Ducts in the Cat. Johns Hopkins Hospital Bulletin, Vol. XVII, No. 181, pp. 1-15, Pls. III-VI, 1906.

HIS, W.—Anatomie menschlicher Embryonen. Bd. III, Leipzig, 1885.

INGALLS, N. W.—Beschreibung eines menschlichen Embryos Von 4.9 mm. Archiv. fiir mikr. Anat. u. Entwicklungsgesch., Bd. LXX, S. 506-576. Taf. XXIX-XXXI, 1907.

JANKELOWITZ, A.—-Ein junger menschlicher Embryo und die Entwicklung des Pankreas bei demselben. Arch. f. mikr. Anat., Bd. XLVI, S. 702-708, 1895.

JANo§fK, J.-—Le pancreas et la. rate. Bibliogr. Anat., pp. 68-73, Tab. I, 1895.

JOUBIN, P. J.—Contribution a Fétude du pancreas chez le lapin. Anat., pp. 203-212, 1895.

KOLLMANN, J.—Handatlas der Entwickelungsgeschichte des Menschen. Jena, Bd. II, 1897.

OPIE, E. L.—Anato1ny of the Pancreas. XIV, No. 150, pp. 229-232, 1903.

OWEN, R.—Comparative Anatomy and Physiology of Vertebrates. Vol. III, 1868.

PHISALIX.—]*jtude d’ un embryon humain de 10 mm. Arch. de Zoolog. Exp. et Générale, Sér. 2, Tome VI, 1888.

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SANTORINI, J. D.—Anatomici summi septemdecim tabulae quas edit. Michael Girardi. Parmae, p. 150, tabulae XII et XIII, 1775.

SCHIRMER, M.——Beitrag zur Geschichte und Anatomie des Pankreas. diss. Basel, 1893.

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SWAEN, A.—-Recherches sur le développement du foie, du tube digestif, de l’arriere—cavité du péritoine et du mésentere. Deuxieme Partie.
Journ. de 1’Anat. et de la Physio1., pp. 32-99, Pls. I-II; pp. 222-258, Pl. VII; pp. 525-585, P15.’ XVI-XVII, 1897.

SYMINGTON, J.—Note on a rare abnormality of the pancreas.
and Physiol., Vol. XIX, p. 292, 1885.
iyntagma anatomicum. 1664.
A\1'4L\, U.-—Beitr£ige zur Entwickelung des‘ Pankreas bei den Amnioten. “Arch. f. mikr. Anat., Bd. LIX, Heft 1, S. 62-93, 1902.

Uber die Verlagerung des dorsalem Pankreas beim Menschen. Arch. f. mikr. Anat., S. 727-733, 1903.

WIRSUNG, G.~—figura ductus cujusdam cum multiplicibus suis ramulis noviter in pancreate observ. Padoue, 1642.

WLAssow.—Zur Entwicklung des Pankreas beim Schwein. Bd. IV, S. 67-76, Taf. V, 1895.

ZIMMERMANN.—Rekonstruktionen eines menschlichen Embryos Von 7 mm.

Verh. d. Anat. Ges., 3 Vers. Berlin. Anat. Anz., Bd. IV, supp1., S. 139-142, 1889.

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Morphol. Arb.,



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