THE MAMMALS 



231 



Fig. 130. The duck-moles are the only mammals which 

 lay eggs. One egg a year is deposited in a carefully con- 

 structed nest where the young are hatched. Another order 

 (Edentata) includes a number of South and Central Ameri- 

 can forms, among which are the ant-eaters, armadillos, 

 and tree-inhabiting sloths (Fig. 129). Still another order 

 (Sirenia) includes the fish-shaped marine dugong and sea- 

 cows or manatees, of which one species is found occasion- 

 ally on the Florida coast. The remaining orders are de- 

 scribed in the succeeding sections. 



217. The opossums and kangaroos (Marsupialia). The 

 lowest order of mammals represented in the United States 



FIG. 131. Opossum (Didelphys virginiana). One-tenth natural size. Photograph 

 by W. H. FISHER. 



is that of the marsupials. It includes the opossums and 

 kangaroos, together with a number of comparatively small 

 and unfamiliar animals living chiefly in and about Australia. 

 16 



