THE DISTRIBUTION OF ANIMALS 449 



delight in lakes and rivers, and moles are subterranean. 

 As of birds, the aquatic species abound in the polar 

 regions. Marsupials inhabit two widely separated areas 

 America and Australia. Tn the latter continent they 

 constitute two thirds of the fauna, while nearly all placen- 

 tal mammals, except bats and a few rats and squirrels, 

 are wanting. Excepting a few species in South Africa 

 and South Asia, edentates are confined to tropical South 

 America. The equine family is indigenous to South 

 and East Africa and Southern Asia, while their fossil 

 remains are abundant in both North and South 

 Ameripa. In North America, rodents form about one 

 half the number of mammals ; there are very few 

 species in Madagascar. Ruminants are sparingly 

 represented in America. Carnivores flourish in every 

 zone and continent. The prehensile-tailed monkeys 

 are strictly South American ; while the anthropoid apes 

 belong to the west coast of Africa, and to Borneo and 

 Sumatra. Both monkeys and apes are most abundant 

 near the equator ; in fact, their range is limited by the 

 distribution of palms. 



