KOALA. 



developed specimen may reach 5 cm. in length. At the 

 portal interval, which really corresponds to a space 

 between the three main divisions of the liver the cystic 

 duct is joined by two hepatic ducts and becomes the com- 

 mon bile duct. 



Hepatic Ducts. — On the left side the left hepatic 

 trunk is formed by the junction of 2 main branches, one 

 from the intermediate and left cystic, and the other from 

 the left lateral lobe. The right hepatic trunk, which is the 

 more proximal, receives branches from the right c^ystic 

 and right lateral lobe. 



The Common Bile Duct passes down to the duode- 

 num, lying in a groove with the artery and portal vein at 

 the junction of the caudate and spigelian lobes, the portal 

 vein being dorsal to the duct as in the human liver. It 

 runs at first in the right extremity of the lesser omentum, 

 being related to pancreatic tissue, and finally enters the 

 meso-duodenum. In this Marsupial the lesser omentum is 

 definable though continuous with the meso-duodenum. 

 The descending duodenum can be lifted from the right 

 kidney and right lateral lobe of the liver, but the meso- 

 duodenum is short and the right part of the pancreas is 

 relatively fixed, and so a definition is made at the common 

 duct, artery, and vein, between the meso-duodenum and 

 lesser omentum. The length of the common duct is about 

 5 cm., and it terminates in the descending pole of the duo- 

 denum 4-5 cm. from the pyloric sphincter. There may or 

 may not be a slight dilatation before it terminates. Un- 

 like the monotremes and certain of the Marsupials, the 

 pancreatic duct opens into the duodenum independently 

 of the common bile duct. 



76 



