172 



LAND MAMMALS IN THE WESTERN HEMISPHERE 



able to maintain their footing in the southern continent and 

 several became extinct during and at the close of the Pleistocene 

 epoch, as was even more markedly the case with the southern 

 forms which invaded the northern continent. 



Fig. 90. — Spectacled Bear [Tremarctos ornatus). — By permission of the 

 N.Y. Zoblog. Soc. 



There are two families of monkeys in the forested areas 

 of South America, both very different from those of the Old 

 World. One of these families, the marmosets (Hapalidse), dif- 

 fers from all other monkeys in several particulars, most obvious 

 of which are the long claws on the feet and the non-opposable 

 thumb. The second family (Cebidse) comprises forms which 

 are superficially much more like those of the eastern hemi- 

 sphere, but many of them have prehensile tails, which are used 

 as efficient grasping organs. 



Insectivora are entirely absent from the South American 



