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.\—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 Didelphys is a very large one, con- 
taining, according to Mr. O. 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 (J. 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 
* Hliger, Prod. Syst. Mami. et Aves, p. 76 (1811). 
* Linn. Syst, Nat. Ed. 12, vol. i. p. 71 (1766). 
