170 



THE GEOGRAPHY OF MAMMALS 



only the genus Cariacus (the Virginian Deer) occurs, the 

 Bison (though formerly inhabiting this Sub-region) not 

 having been seen east of the Mississippi for the last forty or 

 fifty years. 



The Rodents, as in the other Sub-regions, make up the 

 great mass of the mammalian genera, numbering seventeen 

 in all, including Neofiber. 



The Carnivores, Insectivores, and Bats do not differ very 

 markedly from those of the Western Sub-region. 



On the whole the Eastern Sub-region is not a very 

 well-marked division ; it differs from the Canadian chiefly 

 in the non-existence of the numerous northern Palseogean 

 types found there, and from the Western Sub-region in 

 the absence of a good many characteristic desert-haunt- 

 ing forms, and also of several of the South American 

 genera, which have spread up northwards from the 

 Nearctic Region into the Western Sub-region, but which 

 have not reached the more distant Eastern. 



The following table gives a summary of the genera of 

 this Sub-region, from which it will be seen that the total 

 number (forty) of genera is markedly less than the 

 corresponding number in the Arid Sub-region. 



