Mammalia. 269 



around. It is peculiar in having a horn on the top of 

 the snout. In some species there are two horns, not paired, 

 however, but one in front of the other. These animals are 

 found in Africa. and East India. 



The Artiodactyls. The artiodactyls, or even-toed un- 

 gulates, have either two or four toes. These are symmetri- 

 cally arranged on each side of a median cleft ; hence they 

 are spoken of as " cloven-footed" animals. Lowest among 

 the even-toed ungulates are the hippopotamus and the 

 swine. A species of wild hog, the peccary, inhabits Central 

 and South America, extending into Texas. It is a slender, 

 active, fearless animal, in marked contrast to our inactive, 

 fat-burdened domestic hog. The swine are omnivorous, 

 the other ungulates are almost strictly herbivorous. 



Except the camel, nearly all the artiodactyls have four 

 toes, two well developed and two rudimentary. The well- 

 developed toes are the third and fourth, the first toe (cor- 

 responding to our great toe and thumb) being wanting. 

 The second and fifth toes are small, but usually with 

 distinct hoofs ; they are shorter and back of the two main 

 parts of the hoof. These rudimentary hoofs are commonly 

 called the " dewclaws." They do not ordinarily reach the 

 ground, and are of little if any use, except in the reindeer. 



The Ruminants. With the exception of the hippopota- 

 mus and the swine, all the even-toed ungulates are cud 

 chewers and have complex stomachs. As an example, let 

 us consider the cow. There are no upper incisors ; grass 

 and herbage are bitten or broken off by pressing the lower 

 incisors against the hard, toothless pad of the upper jaw. 

 The molars are well developed, and the lateral chewing 

 motions of the jaw are well known. In keeping with this 

 lateral motion, the ridges on the crowns of the molars run 

 lengthwise in wavy lines. The stomach consists of four 



