Ixxxviil REPORT—1858. 
small Kangaroo, and a few Phalangers, exist in islands that link the 
Malayan Archipelago with the Australian world. All the other marsupial 
genera, indeed every known genus save Didelphys, are found in Australasia, 
comprising New Guinea, Australia, and Tasmania. 
The Kangaroos, Potoroos, Wombats, Koalas, Phalangers, Petaurists, Dasy- 
ures, and marsupial quadrupeds of insectivorous and carnivorous habits, 
distinguished only by scientific names, here perform the parts assigned to non- 
marsupial Mammalia in the Old World. No existing marsupial quadruped 
has been found native in continental Asia, in Africa, or in Europe. 
Of the Australasian marsupials the species of New Guinea are distinct, and 
some of them subgenerically, from those of Australia proper. 
Certain genera, as Zarsipes, Cheropus, Phascolarctus, are peculiar to 
Australia; other genera, as Thylacinus and Sarcophilus, the largest and 
most destructive of carnivorous marsupials, are peculiar to Tasmania. 
No marsupial fossil has been found in the pliocene or pleistocene deposits 
of Europe, Asia, or Africa. In America, only representatives occur of the 
peculiarly American genus Didelphys. In the formations of these recent 
tertiary periods, and in the limestone caverns, of Australia, abundance of 
mammalian fossils have been found, and, with the exception of a single tooth 
of a Mastodon, every one of them has proved to be a marsupial species. 
Many belong to the genus of Kangaroos (Macropus), some to that of Poto- 
roos (Hypsiprymnus) ; a few to the Wombats ( Phascolomys), Dasyures (Da- 
syurus), and other existing genera. Some of these fossils have shown that the 
Thylacinus and Sarcophilus formerly inhabited Australia as well as Tasmania. 
Others exhibit the carnivorous or Dasyurine modification of the marsupial 
type in species equalling the Leopard and the Lion in size; and the latter 
with modifications of the carnassial teeth of generic value. We now know 
that there once existed in Australia species of Wombat equalling the Tapir 
in stature ; and species most nearly allied to Macropus, but with characters of 
Phascolomys and Phascolarctus combined, which rivalled the Ox and Rhi- 
noceros in bulk. The skull of the Mototherium presents the strangest pro- 
portions and features hitherto seen in the mammalian class: that of the 
Diprotodon is 3 feet in length, and combines the scalpriform incisors of the 
Wombat with the double-ridged molars of the Kangaroo. 
The sum of all the evidence from the fossil world in Australia proves its 
mammalian population to have been essentially the same in pleistocene, if not 
pliocene times, as now; only represented, as the Edentate mammals in South 
_ America were then represented, by more numerous genera, and much more 
gigantic species, than now exist. 
But geology has revealed more important and unexpected facts relative to 
the marsupial type of quadrupeds. 
In the miocene and eocene tertiary deposits, marsupial fossils of the 
American genus Didelphys have been found, both in France and England ; 
and they are associated with Tapirs like that of America. In amore ancient 
