232 E. A. BAUM GARTNER 



In another embryo of approximately 13 mm. length, which 

 is somewhat more advanced, the ductus choledochus is longer 

 and of larger caliber (figs. 18 and 19). It is, however, still 

 attached to the cranial surface of the anterior fold of the duo- 

 denum. The epithelium here is now definitely columnar in 

 type, though yolk-granules are still present. In this case the 

 pancreatic duct is attached near the gut to the common duct.^ 

 In an embryo 13.5 mm. long the ductus choledochus (fig. 7-A) 

 is attached in a fold to the left side of the gut. The duct here 

 is large but shortly divides into the right and left hepatic ducts. 

 The attachment of the duct to the left wall of the gut is to be 

 seen in a less completely developed embryo 14 mm. long. From 

 now on the common duct is attached to the left side of the gut 

 which is faced somewhat cranialward, due to its growth anteriorly 

 and to the right. The length of the common bile-duct before 

 its division varies. In a 35 mm. embryo modelled the com- 

 mon duct is quite long and has a distinct turn shortly before 

 it entered the gut. Here again the pancreatic duct opens into 

 the common duct. There has been a continual change of posi- 

 tion of the two ducts from the earliest stage to the fully developed 

 one. In an embryo 13 mm. long a distinct pancreatic duct is 

 seen ventral to the common duct. In the further development 

 with the gradual rotation of the liver to the right there has 

 been a change in position of the common duct until in the 35 

 mm. embryo it lies to the left of the pancreatic which is the 

 condition found in the adult (fig. 44). 



c. Development of the major hepatic ducts. The earliest indi- 

 cation of the hepatic ducts was pointed out in the description 

 of the formation of the liver. In a model of an embryo approxi- 

 mately 5 mm. long, as previously stated, the cavity of the early 

 hepatic anlage extends far laterally. On either side the cavity 

 is constricted dorso-ventrally. From the drawings shown by 



- In the further study of the pancreas it was found that this duct was attached 

 by means of a small tubule to the left side of the ventral duct of the pancreas. 

 The epithelial lining resembled that of the gall-biadder, for which this duct 

 was mistaken at first. It might very well be a pancreatic bladder. The pan- 

 creatic duct in this embryo was to the right of the enlarged duct. 



