DISTRIBUTION OF MARSUPIALS AND MONOTREMES 319 



remarkable form of structure, necessitating the formation 

 of a new family, has been found in Australia, and Mr. 

 Thomas himself has shown the necessity of adding to the 

 Neotropical section a Marsupial which is more allied to 

 the Australian forms than to those previously known from 

 America, and which necessitates the creation of a second 

 Neotropical family. We have now, therefore, to deal with 

 eight families of Marsupials, six of which belong to the 

 Australian Region and two to America. These families 

 embrace altogether about 172 species, of which 144 are 

 Australian and 28 are American. According to Mr. 

 Thomas's arrangement, these are divisible into two large 

 groups, the Diprotodonts, which are mostly vegetable-eating 

 animals, and the Polyprotodonts, which feed generally on 

 flesh and insects. 



Section III. — Distribution of Diprotodont 

 Marsupials 



The Kangaroos, or Macropodidse, which form the first 

 family of the Diprotodont section, are a numerous group 

 embracing altogether more than sixty known species. 

 These are distributed all over the Australian Region, but 

 are specially abundant in Australia, where, as is well known, 

 the Kangaroos form one of the most striking features 

 of its peculiar mammal-life. In New Guinea and the 

 Papuan Islands Kangaroos are by no means so abundant, 

 especially those of the genus Macropus and the larger allied 

 forms. On the other hand Dorcopsis and other smaller 

 forms of Kangaroos range through the Papuan Sub-region 

 up to Wallace's line, and New Guinea is especially peculiar 



