94 ANATOMY OF THE WOOD RAT 



ination of the present genus was made, but sections of the 

 stomachs of allied, cricetine rodents show that the glands 

 are tubular and of the parietal type. It is entirely possible 

 that their high specialization and sharp differentiation is 

 connected with some special function. 



In Neotoma the stomach is more nearly spherical, measur- 

 ing 32 by 33 by 14 in one specimen, and 29 by 39 by 15 mm. 

 in another, and in muscularity is fairly intermediate between 

 Homodontomys and Neotoma. The cardiac horn had a 

 length of 20 mm. in one specimen and 22 in the other, while 

 the pyloric horn measured 18 and 21 mm. respectively. 

 In this subgenus the fundus gland was similar and 21 mm. 

 in diameter. 



In Teonoma the specialization is more pronounced, with 

 longer horns to the stomach. In two specimens the latter 

 member measured 41 by 27, and 48 by 27. The cardiac 

 was heavily striated with tough muscle and glandular folds, 

 and the pyloric horn was also well muscled. In places this 

 portion of the stomach wall is 4 mm. thick, as compared 

 to paper thin to one millimeter in Homodontomys. There 

 is a definite constriction at the pyloric valve and the 

 oesophagus joins the stomach at a point farther from the 

 tip of the horn. In this subgenus the fundus area had a 

 diameter of about 27 mm., was thicker, and of a dark green 

 color, the last point probably being due to the herbaceous 

 nature of the food. 



Spleen. The spleen is located dorso-caudad upon the 

 cardiac horn of the stomach. In a single specimen of 

 Teonoma one-third of the spleen was bent at right angles to 

 the remainder, but in all other examples it was straight. 

 In Homodontomys it measured about 25 by 7 mm. ; in Neo- 

 toma 28 by 7 mm.; and in Teonoma, 37 by 8 mm. 



Pancreas. This is of considerable extent but is not 

 unusual. 



Small intestine. In most mammals the small intestine 



