ause it appears to be a most interesting and instructive problem. It
is very seldom that we can trace the animals of a district so clearly as
we can in this case to two definite sources, and still more rarely that
they furnish such decisive evidence of the time, the manner, and the
proportions of their introduction. We have here a group of Oceanic
Islands in miniature--islands which have never formed part of the
adjacent lands, although so closely approaching them; and their
productions have the characteristics of true Oceanic islands slightly
modified. These characteristics are: the absence all Mammalia except
bats; and the occurrence of peculiar species of birds, insects, and land
shells, which, though found nowhere else, are plainly related to those
of the nearest land. Thus, we have an entire absence of Australian
mammals, and the presence of only a few stragglers from the west which
can be accounted for in the manner already indicated. Bats are tolerably
abundant.

Birds have many peculiar species, with a decided relationship to those
of the two nearest masses of land. The insects have similar relations
with the birds. As an example, four species of the Papilionidae are
peculiar to Timor, three others are also found in Java, and one in
Australia. Of the four peculiar species two are decided modifications
of Javanese forms, while the others seen allied to those of the Moluccas
and Celebes. The very few land shells known are all, curiously enough,
allied to or identical with Moluccan or Celebes forms. The Pieridae
(white and yellow butterflies) which wander more, and from frequenting
open grounds, are more liable to be blown out to sea, seem about equally
related to those of Java, Australia, and the Moluccas.

It has been objected to in Mr. Darwin's theory, of Oceanic Islands
having never been connected with the mainland, that this would imply
that their animal population was a matter of chance; it has been termed
the "flotsam and jetsam theory," and it has been maintained that nature
does not work by the "CHAPTER of accidents." But in the case which I
have here described, we have the most positive evidence that such has
been the mode of peopling the islands. Their productions are of that
miscellaneous character which we should expect front such an origin;
and to suppose that they have been portions of Australia or of Java
will introduce perfectly gratuitous difficulties, and render it quite
impossible to explain th