278 POUCHED MAMMALS. 
in a perfectly naked muzzle; while in the larger species the body becomes 
proportionately stouter. 
As regards habits, all the opossums, with the exception of the water-opossum, 
are arboreal, and omnivorous or insectivorous in their diet. They are nocturnal, 
and spend the day concealed either among the foliage of trees or in hollows in 
their trunks or boughs. The opossums take the place in America of the 
Insectivores of the Old World. They are naturally forest-loving animals; but 
a few are found on the pampas of Argentina, where they have adapted themselves 
to a terrestrial life. In those species in which the pouch is rudimental or wanting, 
the young after leaving the teats are carried upon the back of their female parent, 
where they maintain their position by curling their tails round that of their mother, 

COMMON OPOSSUM (t nat, size), 
which is bent forwards for the purpose. Opossums are essentially characteristic 
of Central and South America, only one out of some twenty-four species ranging 
into North America, where it extends as far north as the United States. 
The true opossums, of which there are about twenty-four living 
species, are characterised by the absence of webbing between the 
toes, and by their arboreal habits. The common or Virginian opossum (Didelphys 
marsupralis) is the sole representative of the first group, and likewise the only 
species found in the northern half of America. It is from three to five times 
the size of any other species, and characterised by its long, sealy, prehensile 
tail, and by the fur consisting of a mixture of long bristle-like hairs and a fine 
under-fur. It may be compared in size to a cat, the length of the head and 
body reaching 22 inches in large specimens, and that of the tail 15 inches. 
It is, however, subject to great variation both in size and colour, and on this 
account has received a number of distinct names, the common South American 
True Opossums. 
