THE GEOGRAPHICAL DISTRIBUTION OF MAMMALS 



181 



a creature not much larger than a hare, with almost rudimen- 

 tary antlers" (Lydekker). Old World types of deer, such 

 as the Wapiti, Moose and Caribou, of the Boreal and Transi- 

 tion zones of North America, are entirely absent from the 

 Neotropical region. 



South America has an astonishingly rich and varied assem- 

 blage of rodents, both indigenous and immigrant, but the 



Fig. 102. 



-Wood Brocket {Mazaina nemorivagus). — By permission of 

 W. S. Berridge, London. 



former are much the more important, varied and abundant. 

 Of the four divisions of the order, all of which are represented, 

 three are immigrants from the north and the fourth is autoch- 

 thonous, but this far outnumbers the other three combined. 

 The hares and rabbits have but very few species, one of which 

 occurs in Brazil and is separated by a very wide interval from 

 the one in Costa Rica, while the pikas are absent. Of the squir- 

 rel division, only the true squirrels are found, and of these there 

 are many species, the ground-squirrels, marmots, prairie-dogs 



