THE GEOGRAPHICAL DISTRIBUTION OP MAMMALS 179 



Andes afford a pathway by which the mammals of the south 

 temperate zone extend their range to the equator. 



The suborder Pecora of the Artiodactyla is represented in 

 the Neotropical region only by the deer family {Cervidce), of 

 which there are several genera (or subgenei^a), all of them 

 North American as distinguished from the Old World type, 



Fig. 100. — Florida Deer {Oducoileus virgimatLu:, u-ccola). — By pLrnurHLin l.i the 



N.Y. Zoolog. Soc. 



but some are so peculiar that they must have had a relatively 

 long South American ancestry. The Virginia Deer (Odo- 

 coileus virginianus) of the northern United States is a com- 

 paratively large animal, becoming much smaller in Florida 

 and the Southwest. The type extends through Mexico and 

 Central America to Guiana and Peru, the Neotropical forms 

 being so small and having such weak antlers that they are 

 referred to separate species. Another type is the Marsh Deer 



