INTRODUCTION. xl 
therium should have migrated from opposite extremes, 
and have met in the temperate latitudes of North Ame- 
rica, where, however, their remains are much more scanty 
than in their own proper provinces. 
Australia im like manner, yields evidence of an analogous 
correspondence between its last extinct and its present 
aboriginal Mammalian Fauna, which is the more inte- 
resting 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 re- 
presentatives in that group of many of the orders of 
the more extensive placental sub-class of the Mam- 
malia of the larger continents have also been recog- 
nised in the existing genera and species :—the Dasyures, ‘ 
for example, play the parts of the Carnivora, the Bandi- 
coots of the Jnsectivora, the Phalangers of the Quadru- 
mana, the Wombat of the Rodentia, and the Kangaroos, 
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 marsu- 
pial genera :—some, as the Thylacine, and the Dasyurine 
sub-genus represented by the Das. ursinus, are now ex- 
tinct on the Australian continent, but one species of each 
still exists on the adjacent island of Tasmania; the rest 
were extinct Wombats, Phalangers, Potoroos and Kanga- 
roos, some of the latter being of gigantic stature. Sub- 
sequently, and after a brief interval, we obtain a know- 
ledge of the former existence in Australia of a type of 
the marsupial group, exemplified by the genera Diprotodon 
and Nototherium,* which represented the Pachyderms of 
See “* Catalogue of Fossils in the Museum of the College of Surgeons,” 4to., 
» pp. 291, 336, pls. vi, x 
— 
5 
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