266 



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 



wdMm 



TASMANIA^ WOMBAT (ON THE LEFT) AND HAIRY-NOSED WOMBAT (OB THE RIOHT;. (J Hat 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 



