438 OK. C. F. SONNTAG ON THE 



The ccecum (text-fig. 14 B), 3 inches long, is wide and 

 capacious, and is sacculated by longitudinal bands on its dorsal 

 and ventral surfaces. It has a well-marked mesentery, but no 

 artery occui)ies its free edge. There is no appendix vermi- 

 formis. 



The ileo-ca'cal orifice is guarded by a circular valve. 



Peyer's Patches are absent entirely. I also found no trace of 

 them in Papio anubis. 



There is nothing peculiar to note about the peiitoneum. The 

 mesenteric vessels run straight to the gut, and do not form tiers 

 of arterial arcades. Reaching the bowel they bifurcate, and the 

 halves unite with those of the neighbouring vessels. Several 

 small lymphatic glands are situated along the vessels at the 

 point where they reach the gut. 



The entire mesentery and great omentum are devoid of fat. 



The Salivary Glands. 



The parotid ijkmd (text-figs. 9 A; 17) consists of a large trian- 

 gular superficial part, with small closely-packed Icbules, and a 

 deeper part, with larger lobules. In the latter there are many 

 large vessels and nerves. 



The suhlingiial glands are the size of hazel nuts. They are 

 closely applied to the inner border of the mandible, and the 

 branches of the lingual nerves disappear under cover of them. 



The sihbmaxillary glands are large, circular, and flat, and have 

 a large blood supply from the external carotid arteries. They 

 lie immediately posterior to the fused anterior bellies of the 

 digastric muscles. They are, however, relatively smaller in pro- 

 portion to the size of the animal than those in many other 

 Cercopithecidse. 



The Pancreas. 



One of the most notable features in the anatomy of the Drill 

 is the small size of the pancreas. It is almost black in colour, 

 and its component lobules are just visible to the naked eye. It 

 has a thin tail and an expanded body, but there are no lateral or 

 accessory parts. The total length is three and a quarter inches, 

 and the thickness is two millimetres. The head is one inch wide, 

 and the tail is a quarter of an inch across. The duct unites with 

 the common bile-duct. 



Many arteries run into it from the splenic artery. 



The Liver (text-fig. 15 A). 



The liver is square in shape, as in Papio anubis (2), but it is 

 thin throughout. The gall-bladder is pj'riform, contained in a 

 well-marked fossa, and continued into a long, slender bile-duct 

 which unites with other hepatic ducts to form a long common 

 bile-duct. The latter unites with the pancreatic duct, but there 

 is no bile papilla in the duodenum. The lobes of the liver differ 



