THE MAMMALS 



239 



Fig. 131. The duck-moles are the only mammals which 

 lay eggs. These are deposited in a carefully constructed 

 nest where the young are hatched. Another order (Eden- 

 tata) includes a number of South and Central American 

 forms, among which are the ant-eaters, armadillos, and tree- 

 inhabiting sloths (Fig. 130). Still another order (Sirema) 

 includes the fish-shaped marine dugong and sea-cows or 

 manatees (Fig. 132), of which one species is found occasion- 

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

 scribed in the succeeding sections. 



223. The opossums and kangaroos (Marsupialia). The 

 lowest order of mammals represented in the United States 



FIG. 133. Opossum (Didelphys virginlana). 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. 



