PHYSIOLOGY, AND PATHOLOGY OF THE CHIMPANZEE. 373 



than in Ma,n. The great curvatiii-e reaches a point half an inch 

 below the fourth lumbar vertebra, and the lowest point of the 

 lesser curvature is level with the first lumbar vertebra. Con- 

 sequently the stomach is U -shaped, and the pylorus is not far 

 from the oesophagus. The pyloric antrum is one and a half 

 inches long, and the pylorus, whose walls are thick, is of the 

 same length. Between the antrum and pylorus there is a slight 

 incisura, and there is a sudden transition from the pylorus to the 

 duodenum. The pylorus does not project like a knob into the 

 duodenum as it does in Man. 



The serous coat is a uniform covering, united in the usual 

 manner to the omenta. The muscles are thin, but three kinds 

 are present. The external longitudinal layer is a complete 

 covering, but it is thicker along the curvatures than on the 

 intermediate parts of the body. The circular fibres are thickest ; 

 they are found in the body and pylorus, but only a few run 

 from the cesophagus into the fundus. The oblique fibres are 

 restricted to the fundus and part of the body to the left side of 

 a downward prolongation of the long axis of the oesophagus, and 

 they form rings as in Man. Consequently there are only two 

 muscular layers — an outer one of longitudinal fibres, and an 

 inner one of oblique fibres to the left and circular ones to the 

 right. The subserous aud suhmucous coats are thin. The onucous 

 membrane is thin, and some of the gastric arteries are seen 

 ramifying in the wall of the stomach. So thin is it that the red 

 injection matter in the vessels shines up prominently against the 

 pale mucosa. It is succulent and its surface shows the areas and 

 glandular orifices as in Man. Only a few longitudinal rugae are 

 present. 



Blood Sitpply : — The coronary artery (text-fig. 40 A) runs along 

 the lesser curvature along with branches of the left vagus nerve ; 

 it gives off toi-tuous gastric arteries to both surfaces (a.g.a and 

 p.g.a), and oesophageal arteries which pass up thi'ough the 

 oesophageal opening in the diaphragm. The parent artery anas- 

 tomoses with the right gastric branch of the hepatic artery. The 

 splenic artery sends branches to the greater curvature (g.c.b) and 

 the left gastro-epiploic artery, which anastomoses in the great 

 omentum with the right vessel from the hepatic artery. The 

 hepatic artery, in addition to the branches, sends superior pyloro- 

 duodenal arteries downwards, and these meet with inferior 

 pyloro-duodenal branches of the coeliac axis ; from both the 

 stomach receives branches. The gastric veins open into the 

 portal system (text-fig. 43). Barkow (3) has given an illustra- 

 tion of the stomach and its vessels. 



Nerves : — The left vagus sends branches along the lesser cur- 

 vature as far as the pylorus, and some other twigs form a plexus 

 over the lower end of the oesophagus. The right vagus sends a 

 rich supply of nerves to the stomach through the splenic plexus 

 and coronary plexus, and directly. 



Pkoc. ZooL. See— 1923, No. XXV. 25 



