ON THE EXTINCT MAMMALS OF AUSTRALIA. 239 



of the Muridce in South America ; and that not one fossil is referable to a 

 true Old World Mus, though numbers of the common Rat and Mouse have 

 been imported into South America since its discovery by Europeans. With 

 regard to the Sloths and Armadillos, they now seem, after the rich harvest of 

 bulky Glyptodons, Mylodons, Pachytheriums, and the more gigantic Mega- 

 therioid species, to be the last remnants of a jMammalian Fauna which once 

 almost equalled in the size and number of its species that of the Europseo- 

 Asiatic expanse, and was as peculiarly characteristic of the remote continent 

 in which almost all its representatives have been entombed. 



In North America the most abundant Mammalian fossils of the correspond- 

 ing recent geological epoch belong to a species of Mastodon (M, giganteus) 

 peculiar to that continent. Since, however, North America borders closely 

 upon Asia at its northern basis, and is connected by its opposite apex with 

 South America, it perfectly accords with the analogies of the geographical 

 relations of the last-extirpated series of Mammals of the Old World that the 

 Asiatic Mammoth and the South American Megatherium should have mi- 

 grated from opposite extremes, and have met in the temperate latitudes of 

 North America, where, however, their remains are much more scanty than 

 in their own proper provinces. 



Australia at length begins to yield evidence of an analogous correspondence 

 between its latest extinct and its present aboriginal Mammalian Fauna, which 

 is the more interesting on account of the very peculiar organization of most 

 of the native quadrupeds of that division of the globe. That the Marsupialia 

 form one great natural group is now generally admitted by zoologists; the 

 representatives in that group of many of the orders of the more extensive 

 placental sub-class of the Mammalia of the larger continents have also been 

 recognised in the existing genera and species : — the Dasyures, for example, 

 play the parts of the Carnivora, the Bandicoot of the Insectivora, the Pha- 

 langers of the Quadrwnana, the Wombat of the Rodentia, and the Kanga- 

 roos, in a remoter degree, that of the Ruminantia. The first collection of 

 Mammalian fossils from the ossiferous caves of Australia brought to light the 

 former existence on that continent of larger species of the same peculiar mar- 

 supial genera : — some, as the Thylacine, and the Dasyurine sub-genus repre- 

 sented by the Das. ursinus, are now extinct on the Australian continent, but 

 still exist on the adjacent island of Tasmania ; the rest being Wombats, Pha- 

 langers, Potoroos and Kangaroos, the latter of portentous stature. Subse- 

 quently, and after a brief interval, we obtain a knowledge of the former 

 existence of a type of the marsupial group which represented the Pachyderms 

 of the larger continents, and which seems now to have disappeared from the 

 face of the Australasian earth. 



I cannot conclude without adverting to the singular exception which the 

 Mastodon forms to that continental localization, not only of existing, but of 

 pliocene and post-pliocene extinct genera of Mammalia above briefly dwelt 

 upon. The solitary character of the exception helps rather to establish the 

 generalizations, at least I know of no other extinct genus of Mammal which 

 was so cosmopolitan as the Mastodon : it was represented by species, for the 

 most part very closely allied, if actually distinct, in Europe, in Asia, in North 

 and South America, and in Australia; it is the only aboriginal genus of qua- 

 druped in that continent which was represented by other species in other parts 

 of the world. 



The most remarkable local existing FaurTa, in regard to terrestrial verte- 

 brated animals, is that of the islands of New Zealand, with which geologists 

 have been made familiar by Mr. Lyell's indication of its close analogy 



