xv HABITS OF RHIZOMYS 483 



species the large intestine is slightly shorter than the small 

 intestine. In Rh. Radius the two parts of the gut are almost 

 exactly equal in length. There are three pairs of inguinal and 

 two pairs of pectoral teats. The name Rhizomys appears to have 

 been given to the animals of this genus for the reason that they 

 feed largely on roots. They burrow, and, like many other 

 burrowing animals, feed in the evening. As is the case with 

 other forms, Rhizomys is said to burrow with the assistance of 

 its teeth as well as of its claws. 



FIG. 237. Bamboo Rat. Rhizomys badius. 



Tachyoryctes is an African genus closely allied to the last. There 

 are three Ethiopian species. It is mainly to be distinguished by 

 the different pattern upon the grinding surface of the molars. 



Fam. 5. Geomyidae. This family of burrowing Eodents is 

 limited to North and Central America. The animals have cheek 

 pouches, and small eyes and ears, in accordance with their mode 

 of life. The claws of the fere-limbs are very strongly developed. 



The genus Geomys contains some eight species, which are 

 Central and North American, not extending, however, far north. 

 The incisors of the upper jaw are grooved with two grooves. 

 There are three pairs of teats one axillary, and the two remain- 

 ing inguinal. 



Thomomys, without grooves on the incisors, reaches to Canada 

 in the north, and does not extend as far south as the last genus. 



