FOOD AND DIGESTION 



339 



arranged in two layers, an outer longitudinal layer, and an 

 inner circular layer. 



The Stomach in carnivora and in the pig is a dilatation of 

 the alimentary canal into which the gullet opens. To the 

 left it expands into a sac-like cardiac end (C.\ and to the 

 right it narrows, forming the pyloric end (Py.}. Like the 

 gullet, it is surrounded by visceral muscular fibres, arranged 

 essentially in two sets. At the cardiac orifice, the circular 

 fibres form a not very marked cardiac sphincter, and at the 



. caec. 



?IG. 150. Stomach of the Horse to show R. as. , the cesophageal part ; Fu., the 

 fuudus with true gastric glands ; R. pyl., pyloric part. 



)yloric end they form a very thick and strong pyloric 

 sphincter. 



The mucous membrane, which is covered by a columnar epi- 

 thelium, is largely composed of tubular glands, those at the cardiac 

 3nd containing two kinds of cells, the peptic and the oxyntic 

 ills, those at the pyloric end containing peptic cells alone. 



In the horse the stomach is also a single sac (fig. 150), but 

 the cardiac end is lined by a continuation of the stratified 

 squamous epithelium of the gullet. The opening of this into 

 the stomach is very narrow. The true cardiac mucous mem- 



