168 THE GEOGRAPHY OF MAMMALS 



Edentata, the Nine-banded Armadillo (Tatusia novem- 

 cincta). Among the Ungulates, the Prong-buck (Antilo- 

 capra) is restricted to this Sub-region, and the genus Cervus 

 of the cold Temperate Sub-region is replaced by the purely 

 American genus Cariacus, of which the Black-tailed Deer 

 is the representative. 



This Sub-region is also more particularly the home of the 

 American Bison, which, however, ranged even in historic 

 times eastward nearly to the Atlantic seaboard. Among 

 the Rodents there are no less than five endemic genera, of 

 which, perhaps, the best known is Cynomys, the Prairie- 

 dog. The other endemic genera all belong to the family 

 Geomyidie, which contains a number of small Rodents 

 known as Pocket-gophers. 



Among the Carnivora there are no genera in the 

 Western Sub-region which are not more or less widely dis- 

 tributed, the greater number of them, both in the case of 

 this order and of the last, being also found in the Old 

 World. Three genera of Moles belonging to the next 

 order, Insectivora, though confined to North America, 

 extend into the Eastern Sub-region. The Bats of the 

 Arid Sub-region include among their members two genera 

 (each with one species) which occur only in California, 

 while four other genera are found only in the New World. 

 One of these, Macrotus, is of special interest, since it con- 

 tains the only member of a very large and well-marked 

 family (Phyllostomatidm), which extends into the Nearctic 

 Region from South America. 



This Sub-region, as compared with the Canadian, con- 

 tains a far larger proportion of Neotropical genera, and, in 

 addition, is characterized by the absence of a number of the 

 Palsearctic forms found only in the Canadian Sub-region. 



