578 ZOOLOGY. 
forms being nearly smooth, while, in point of their general 
structure and intelligence, they stand at the foot of the sub- 
class. The teeth may be entirely undeveloped, as in the 
common ant-eater, but when developed they are not encased 
Fig. 499.—Skeleton of the Ai, or Three-toed Sloth.—After Owen 
in enamel. In most Edentates the incisors are absent, but 
the lateral one may exist in the armadillo (Dasypus). The 
feet are formed for grasping or digging, and end in large 
straight or curved claws. They are either hairy or pro- 
