PHYSIOLOGY, AND PATHOLOGY OF THE CHIMPANZEE. 



393 



The external jugular vein (E. J.V) does not lie on the surface 

 of the sterno-mastoid. It dips down and lies on the surface of 

 the common carotid artery, vagus and sympathetic. At the 

 outer border of the first rib it unites with the subclavian vein to 

 form the innominate vein. 



Veins of the Abdomen. 



The Portal Syste7n (text-fig. 43). 



The general arrangement of the tributaries of the portal system 

 is the same as in Man, bub there ai-e differences in detail. The 

 vein formed by the confluence of gastric, splenic and inferior 

 mesenteric veins unites with a large trunk formed by pyloro- 

 duodenal, superior mesenteric veins and the veins from the 



Text-figure 43. 



Tlie portal vein. Letters in test. 



transverse colon to form the portal vein. And the veins from 

 the transverse colon form a connecting loop between the two 

 systems. The portal vein begins behind the pancreas and ascends 

 to the portal fissui-e in the liver behind the hepatic artery and in 

 front of the foramen of Winslow. It divides into two large 

 branches which enter the liver. The main vein is two and a 

 half inches long. It is behind the pancreas, but it is later accom- 

 panied by a process of pancreatic tissue. It is surrounded and 



