134 MARSUPIALIA 



continent, ranging from the United States to Patagonia, the greater 

 number of species being found in the warmer regions. In South 

 America the opossums take the place of the Eutherian Insectivora, 

 and the sharp cusps on their teeth are admirably adapted for crushing 

 the insects on which they mainly subsist. 



Chironectes. 1 The family comprises two genera only, namely 

 Didelphys, containing all the species, with the exception of the curious 

 Yapock, which forms by itself the genus Chironectes, and is distin- 

 guished from all other Opossums by its webbed feet, non-tuberculated 

 soles, and peculiar coloration. Its ground colour is light gray, with 

 four or five sharply-contrasted brown bands passing across its head 

 and back, and thus giving it a very peculiar mottled appearance. 

 It is almost wholly aquatic in its habits, living on small fish, 

 crustaceans, and water insects. Its range extends from Guatemala 

 to southern Brazil. 



Didelphys. 2 The type genus Didelphijs is a very large one, con- 

 taining, according to Mr. 0. Thomas, twenty-three existing species. 

 It may be divided into five groups, or sub-genera, all of which have 

 received distinct names. The typical group is represented only by 

 the common or Virginian Opossum (D. marsupialis), of which the 

 numerous varieties have received separate specific names. This 

 species is of large size, with a long, scaly, prehensile tail, and long 

 bristle-like hairs mingled with the fur. The pouch is complete. 

 It ranges over all temperate North America, and is also found in 

 central and tropical South America, where it is commonly known 

 as the Crab-eating Opossum. This animal is extremely common, 

 being even found living in the towns, where it acts as a scavenger 

 by night, retiring for shelter by day upon the roofs of the houses or 

 into the sewers. The female produces in the spring from six to 

 sixteen young ones, which are placed in her pouch immediately 

 after birth, and remain there until able to take care of them- 

 selves. 



The second or Metachirine group includes three species found 

 all over the tropical parts of the New World. They are of medium 

 size, with short close fur, very long, scaly, and naked tails, and 

 less developed ridges on their skulls than in the type species. As 

 a rule there is no pouch adapted to carry the young, which 

 commonly ride on their mother's back, holding on by winding 

 their prehensile tails round hers. The Philanderine group is 

 closely allied to the preceding, but is readily distinguished by the 

 woolly hair, and the brown streak down the middle of the face. 

 The Woolly Opossum (D. lanigera), which is represented in the 

 accompanying woodcut (Fig. 38) carrying its young in the fashion 

 mentioned above, is one of the two species of this group. In the 



1 Illiger, Prod. Syst. Afamm. et Aves, p. 76 (1811). 



2 Linn. Syst. Nat. Ed. 12, vol. i. p. 71 (1766). 



