THE NATURAL HISTORY OF THE KANGAROO. 
391 
(besides tbe Didelphidce ), in a state of nature, we must go 
much further than merely across the Atlantic; namely, to 
Australia or the islands adjacent to it, including that enormous 
and unexplored island New Guinea, which has recently attracted 
public attention through the published travels of a modern 
Baron Munchausen. 
To return, however, to our subject. To find marsupials at 
all, we have, as we have seen, to go to the New World. To 
find nearer allies of the kangaroo, we must go to the newest 
world, Australia ; newest because, if America merited the title 
of neiv from its new natural productions as well as its new dis- 
covery, Australia may well claim the superlative epithet on 
both accounts. We have found an indication, in the name 
Botany Bay, of the interest excited in the mind of Sir Joseph 
Banks by the new plants as well as by the new animals of 
Australia. And, indeed, its plants and animals do differ far 
more from those of the New World (America) than do those 
of America from those of the Old World. 
Marsupials, in fact, are separated off from the rest of their 
class — from the great bulk of mammals — the Monodelphia — no 
less by their geographical limits than by their peculiarities of 
anatomical structure. 
And these geographical limits are at the same time the 
limits of many groups of animals and plants, so that we have 
an animal population (or fauna) and a vegetable population (or 
flora) which is characteristic of what is called the Australian 
region — the Australian region , because the Australian forms of 
life are spread not only over Australia and Tasmania, but over 
New Guinea and the Moluccas, extending as far north-west as 
the island of Lumbock , while marsupials themselves extend to 
Timor . 
In India, the Malay peninsula, and the great islands of the 
Indian Archipelago, we have another and a very different fauna 
and flora — that, namely, of the Indian region, and Indian forms 
of life extend downwards south-east as far as the island of 
Bali. Now Bali is separated from Lumbock by a strait of but 
fifteen miles in width. But that little channel is the boundary 
line between these two great regions — the Australian and the 
Indian. The great Indian fauna advances to its western margin, 
while the Australian fauna stops short at its eastern margin. 
The zoological line of demarcation which passes through 
these straits is called “Wallace’s line,” because its discovery is 
due to the labours of that illustrious naturalist, that cou- 
rageous, persevering explorer, and most trustworthy observer, 
Alfred Wallace, a perusal of whose works I cordially recom- 
mend to my readers, since the charm of their style is as 
remarkable as is the sterling value of their contents. Mr. 
