260 



Descriptive Zoology. 



they proceed, strip off the leaves. On the ground they 

 are almost helpless. The extinct slothlike megatherium 

 was as large as a rhinoceros. 



The armadillos have a scaly or horny development of 

 the skin for protection ; some have also the power of roll- 

 ing themselves into a ball, still further securing safety. 



The ant-eaters lack teeth ; they secure insects by pro- 

 truding the long, sticky tongue. 



The Gnawers. The gnawers, or rodents, are character- 

 ized by chisel-shaped incisor teeth, which keep wearing 

 away at the tip and as continually growing from the root. 



FIG. 153. NINE-BANDED ARMADILLO. 



From Packard, after Liitken. 



In all but the hares the incisors are two above and two 

 below. There are no canine teeth, and there is a wide 

 space between the incisors and the molars. They are 

 chiefly herbivorous, and the digestive tube is long. They 

 constitute the largest family of mammals, and are espe- 

 cially numerous in individuals. 



The Hares. The general characteristics of this family 

 have been illustrated in the description of the rabbit. 

 Besides our common gray rabbit, there are found in the 

 Southern states the marsh hare and the water hare ; in th< 

 North, the northern hare, which turns white in winter; 

 on the Western plains, the big jack rabbit. 



