44 F. W. THYNG 



can be determined from plate 2. It is situated to the right of 

 the vesica fellea (Ves.fel.), lying between this and the umbilical 

 vein (V.um.s., plate 4). 



The hepatic duct (D.hep., plate 2, and text figure 2) takes 

 origin from the hepatic trabeculae of the medial surface of the 

 right lobe, ventral to the entrance of the portal vein (V.P.). It 

 extends dorsally and to the left for a short distance and then cau- 

 dad, uniting with the small cystic duct (Dxyst) to form the ductus 

 choledochus (D.chol.). 



The cystic duct has a slender lumen, and leads in a nearly 

 dorso-ventral direction from a small, distal dilatation, the gall- 

 bladder (Ves.fel., plate 2). The latter is closely apphed to the 

 ventro-medial surface of the right lobe of the liver. 



The common bile duct is considerably larger in diameter than 

 either the hepatic or cystic ducts. It has a well-defined lumen, 

 and extends caudad through the lesser omentum in an S-shaped 

 course to open into the duodenum. This it does upon its left 

 side, a short distance beyond the pyloric end of the stomach. 

 The epithelium of the gall-bladder and of the cystic and common 

 bile ducts, is devoid of knob-like buds and diverticula, met with 

 in these situations in other embryos. 



Pancreas. The pancreas of this embryo has been described, 

 and pictured in a previous paper (Thyng '08), but for the sake of 

 completeness it will be described briefly in this connection. It 

 consists of two parts, a dorsal and a ventral pancreas {Panc.d. 

 and v., text figure 2). The dorsal pancreas is considerably the 

 larger, and extends distally into the mesogastrium. It is essen- 

 tially a long, irregular, hollow mass of epithelium with prolifer- 

 ating branches of varying length which in turn often give off 

 hollow buds. Its duct (D.panc.d.) is larger than that of the ven- 

 tral pancreas, contains a well-defined lumen, and opens into 

 the left side of the duodenum nearer the stomach than the bile 

 duct. 



The ventral pancreas is in close relation with the proximal 

 part of the dorsal anlage, the two having anastomosed ventral to 

 the portal vein, and on the left of the common bile duct. Like the 



