166 DR. C. F. SONNTAG ON THE 



the rectum where the bile-staining is deepest. It also appears as 

 if there had been a strong septum across the rectum, for there is 

 a ridge round the wall. 



The anus is surrounded by a tough, strong sphincter, and the 

 mucosa is thrown into many longitudinal folds. 



The structure of the whole alimentary tube must be taken into 

 account, in order to understand the physiological significance of 

 the conditions in the rectum. The stomach is complex, as in 

 Ruminants, but the intestinal tube is short, so it is necessary 

 that there be some arrangement to obtain the maximum 

 absorption area in the latter. This is attained b}' the excavation 

 and folding of the mucous membrane of the latter, and the 

 sphincteric valvular openings in the septa across the colon only 

 allow a small amount of material to pass at a time into the rectum. 

 The powerful anal sphincter muscle is also required to ensure 

 a sufficiently prolonged stay of the intestinal contents, for absorp- 

 tion of water (?) may take place slowly in the rectum. 



The reticulum of the Ruminants is absent in the stomach of 

 the Sloth, and the hollows in the rectum resemble the pockets 

 of a reticulum. 



The Pancreas (text-fig. 11, c & d). 



Rapp (10) and others state that the pancreas extends across the 

 abdomen dorsal to the stomach, but in my specimen it is almost 

 entirely contained within the duodenal loop ; none of it lies 

 dorsal to the stomach. It presents features, therefore, which 

 resemble those of the Reptilia. 



It is V-shaped and has splenic and duodenal limbs (si and dl). 

 The former lies between the right border of the ventral limb of 

 the pylorus on the left and the left border of the spleen on the 

 right. The latter lies along the left border of the duodenum, and 

 the angle of the V runs for a short distance anterior and dorsal to 

 the duodenal loop. A short distance distal to the posterior end 

 of the duodenal limb there is a small isolated piece of pancreas (sp). 



The entire organ is surrounded by peritoneum, the splenic limb 

 being enveloped by the layers of the dorsal sheet of the great 

 omentum, and the duodenal limb and isolated mass being included 

 between the layers of the common mesentery. 



The splenic limb consists of a cylindrical massive part and 

 a lateral lamina, but the latter is wrapped round the former 

 (text-fig. 11, D). Within the massive portion there lies a small 

 spherical accessory spleen. The small isolated piece of pancreas 

 is oval in shape. 



The pancreatic duct, contained within the gland, runs along 

 close to the anterior border, receiving tributary ducts as it goes. 

 When it emerges from the end of the duodenal limb it is crossed 

 at right angles by the common bile-duct. It opens into the 

 duodenum at the summit of a prominent papilla. Francaviglia 

 (4), however, saw the duct open along with the common bile-duct. 



