THE MOUSE AND ITS ALLIES 323 



The Edentata, 1 few of which are entirely without teeth, 

 include the sloths, hairy ant-eaters, armadillos, scaly ant- 

 eaters, and aardvarks, or African ant-eaters. The three 

 first-named families inhabit South America ; the two 

 latter, Asia and Africa. Here, again, the discontinuity of 

 the group indicates what fossils prove, that the Edentates 



FIG. 298. Didelphys virginiana, the North American opossum. After 

 Vogt anrd Specht. 



have been killed off from the connecting continents. The 

 sloths have incisor teeth, live in trees, and eat leaves (Fig. 

 299). The armadillos are protected by strong plates de- 

 veloped in the skin ; they are chiefly nocturnal and om- 

 nivorous animals, and burrow rapidly. The other three 

 families feed on ants and termites, lack complete teeth (ex- 

 cepting the aardvarks), and are either arboreal or burrowing. 



1 e, out ; dens, dentis, tooth. 



