448 



ANATOMY OF VERTEBRATES. 



353 



There is no caecum. In the great Ant-eater (Myrmecophaga 

 jubata) the stomach, fig. 353, presents a spherical form, of about 

 8 inches diameter, with a smaller subglobular appendage, as it 

 seems, ib. h, h, of about 3 inches diameter, intervening between 

 the main cavity, c, c, and the intestine, d. The oesophagus, a, 



terminates near the middle 

 of the upper surface of the 

 main, or cardiac, portion. 

 On the middle of both the 

 anterior and posterior sur- 

 faces of the stomach is a 

 sheet ot tendon, which 

 extends from the large 

 to the small division of 

 the organ, expanding upon 

 both divisions, but ac- 

 quiring upon the latter 

 its greatest thickness and 

 whitest colour. The car- 

 diac cavity, c, c, has a 

 vascular secreting surface, 

 the lining membrane being 

 disposed in very numerous 

 small wavy rugae : the 

 larger and apparently more permanent folds converge toward 

 the aperture, /, of the pyloric cavity. The cardiac orifice has 

 the form of a narrow, slightly bent crescentic slit. It is 

 situated about 3J inches from the similarly shaped aperture of 

 communication between the cardiac and the pyloric cavities : 

 but the margin of this latter aperture is indented, as it were, by 

 the ends of the converging folds of the lining membrane, which 

 are continued into the pyloric cavity. The pyloric division is 

 remarkable for the thickness of its muscular tunic and the density 

 of its epithelial lining, which convert it into a veritable gizzard. 

 The muscular coat, ib. h, h, varies from 1 inch to ^ an inch in 

 thickness ; at the middle of the cavity it is separated from the 

 lining membrane by an unusual accumulation of the elastic sub- 

 mucous areolar tissue, i, which is most abundant in the upper 

 wall of the cavity. A very small proportion only of food can 

 enter at one time into this cavity, to be subjected to the triturating 

 force of its parietes, operating, with the aid of swallowed particles 

 of sand, in the comminution of the unmasticated or imperfectly 

 masticated Termites. The area of the pyloric cavity, as exposed 



Stomach of Great Auteutor. 



