2G6 



On the Vitelline Vein of the Cat 



variable amount of mesenchymal tissue, and covered by the mesothe- 

 lium. It is obvious that this vessel cannot be a synonym for the 

 superior mesenteric vein, since that vein lies with the artery of the 

 same name in the mesentery of the small intestine. I know nothing 

 of the development of the superior mesenteric vein, but if one injects 

 the portal system of a cat at birth with very thin Teichmann's mass, 

 the pervious vitelline vein can be seen entering the mesentery of the 



Fig. 7. 



Fig. 8. 



Fig. 7. Embryo of 23.1 mm. Harvard Embryological Collection. Transverse 



series 466. Section 1079. 



Fig. 8. Embryo of 39 mm. Harvard Embryological Collection. Transverse 



series 361. Section. 643. 



duodenum, to join the superior mesenteric vein just previous to the 

 union of that vein with the splenic. In other Avords, the vitelline vein 

 is no more a branch of the superior mesenteric than is the splenic vein. 

 It does not lie in the mesentery of the jejunmn and ileum, neither does 

 it receive blood from the intestines. Its object seems to be to return 

 the blood from the yolk sac to the liver, and in its course it joins the 



