THE VERTEBRATE ANIMALS 



315 



this order, is of considerable value, as are the coats of several 



other rodents. The fur of the rabbit is used in the manufacture 



of felt hats. The quills of the porcupines (greatly developed and 



stiffened hairs) have a 



slight commercial value. 

 Ungulates: Hoofed 



Mammals. -- This group 



includes the domesticated 



animals, as the horse, cow, 



sheep, and pig. A group 



of animals which originally 



roamed wild, many species 



eventually came under the 



subjugating influence of 



man. Now they form a 



source of the world's 



wealth, and are an impor- 

 tant part of the wealth of 



the United States. 



The order of ungulates 



is a very large one. It is characterized by the fact that the nails 



have grown down to become thickened as hoofs. In some cases 



only two (the third and 

 fourth) toes are largely 

 developed. Such animals 

 have a cleft hoof, as in the 

 ox, deer, sheep, and pigs. 

 These form the even-toed 

 ungulates. The deer fam- 

 ily are the largest in 

 number of species and 

 individuals among our 

 native forms, and in fact 

 the world over. Among 

 them are the common 



Virginia deer of the Eastern states, the white-tailed deer of our 



Adirondack forests. The bison, or buffalo, is nearly related to 



the deer and wild cattle. Formerly bisons existed in enormous 



deer. 1'Yoin photograph loaned l>y 

 the American Museum of Natural History. 



The bison. 



