DIGESTIVE SYSTEM. 203 



and the wombat, although in certain rodents a 

 somewhat similar arrangement exists. In carniv- 

 orous animals the cecum is very slightly devel- 

 oped; in herbivorous animals (with a simple stom- 

 ach) it is, as a rule, extremely large. It has been 

 suggested that the vermiform process in man is the 

 degenerated remains of the herbivorous cecum, 

 which has been replaced by the carnivorous. An- 

 other and perhaps more probable view regards the 

 appendix as a lymphoid organ, having the same 

 functions as Peyer's patches and, like these, under- 

 going degeneration after middle life" (Berry). 



In the different parts of the alimentary canal the 

 mucosa shows a marked variation, as represented in 

 the following table : 



Blood Supply of Stomach and Intestines. The ar- 

 teries of the stomach are all derived from the celiac 

 axis, a branch of the aorta. The intestines are sup- 

 plied by blood from the superior and inferior mesen- 

 teric arteries, branches of the aorta. The arteries 

 enter along the line of the mesenteric attachment 

 and there form branches that pass transversely 

 around the intestine to ultimately penetrate the 

 longitudinal muscle layer. Between the two mus- 

 cular coats branches are given off to supply the 



