larger
sort (other than birds) is to be discovered anywhere south of Wallace's
Line. That narrow belt of deep sea, in short, forms an ocean barrier
which has subsisted there without alteration ever since the end of the
secondary period. From that time to this, as the evidence shows us,
there has never been any direct land communication between Australia and
any part of the outer world beyond that narrow line of division.

Some years ago, in fact, a clever hoax took the world by surprise for a
moment, under the audacious title of 'Captain Lawson's Adventures in New
Guinea.' The gallant captain, or his unknown creator in some London
lodging, pretended to have explored the Papuan jungles, and there to
have met with marvellous escapes from terrible beasts of the common
tropical Asiatic pattern--rhinoceroses, tigers, monkeys, and leopards.
Everybody believed the new Munchausen at first, except the zoologists.
Those canny folks saw through the wicked hoax on the very first blush of
it. If there were rhinoceroses in Papua, they must have got there by an
overland route. If there had ever been a land connection between New
Guinea and the Malay region, then, since Australian animals range into
New Guinea, Malayan animals would have ranged into Australia, and we
should find Victoria and New South Wales at the present day peopled by
tapirs, orang-outangs, wild boars, deer, elephants, and squirrels, like
those which now people Borneo, instead of, or side by side with, the
kangaroos, wombats, and other marsupials, which, as we know, actually
form the sole indigenous mammalian population of Greater Britain beneath
the Southern Cross. Of course, in the end, the mysterious and tremendous
Captain Lawson proved to be a myth, an airy nothing upon whom
imagination had bestowed a local habitation (in New Guinea) and a name
(not to be found in the Army List). Wallace's Line was saved from
reproach, and the intrusive rhinoceros was banished without appeal from
the soil of Papua.

After the deep belt of open sea was thus established between the bigger
Australian continent and the Malayan region, however, the mammals of the
great mainlands continued to develop on their own account, in accordance
with the strictest Darwinian principles, among the wider plains of their
own habitats. The competition there was fiercer and more general; the
struggle for life was bloodier and more arduous. Hence, while the
old-fashioned marsupials continued to survi