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POUCHED MAMMALS. 
being reduced to a single functional pair of large size, which are invariably inclined 
forwards. On account of this single pair of functional lower incisor teeth, they are 
collectively termed Diprotodonts. The upper canine or tusk is small in all the 
group, and the corresponding lower tooth absent or represented by a rudiment. 
On the other hand, in the remaining families of the order the incisor teeth, as 
shown in the woodcut on p. 268, are of a more normal type; that is to say, 
they are numerous, and the innermost pair is not greatly developed at the expense 
of the others. The tusks are large and prominent; and whereas in the 
Diprotodonts the molar teeth have broad and often squared crowns, surmounted 
TASMANIAN WOMBAT (ON THE LEFT) AND HAIRY-NOSED WOMBAT (ON THE RIGHT). (g- liat. size.) 
by transverse ridges or blunt tubercles, those of the present group have sharp 
cusps, and are generally more or less triangular in form, thus indicating a partially 
or wholly carnivorous diet. On account of the number of their lower incisor teeth, 
the name of Polyprotodonts has been suggested for this second great group of the 
Marsupials, which occupy the place in the order held by the Carnivores and 
Insectivores among the Placental Mammals. Instead of being restricted to the 
Australasian region, the Polyprotodonts are represented in America by the 
opossums ; while in former epochs they had apparently a world-wide distribution, 
and included some of the oldest mammals known. 
The bandicoots are small or medium - sized animals of fossorial habits, 
living either on insects or a mixed diet, and are readily characterised by the 
structure of their hind-feet. They have long and sharply pointed noses; and the 
