e lands, or by a few intervening islands which have since
disappeared, or it may even be due to human agency.

If the explanation now given of the peculiar features presented by the
fauna of Celebes be the correct one, we are fully justified in classing it
as an "anomalous island," since it possesses a small but very remarkable
mammalian fauna, without ever having been directly united with any {462}
continent or extensive land; and, both by what it has and what it wants,
occupies such an exactly intermediate position between the Oriental and
Australian regions that it will perhaps ever remain a mere matter of
opinion with which it should properly be associated. Forming, as it does,
the western limit of such typical Australian groups as the Marsupials among
mammalia, and the Trichoglossidae and Meliphagidae among birds, and being
so strikingly deficient in all the more characteristic Oriental families
and genera of both classes, I have always placed it in the Australian
Region; but it may perhaps with equal propriety be left out of both till a
further knowledge of its geology enables us to determine its early history
with more precision.

_Peculiarities of the Insects of Celebes._--The only other class of animals
in Celebes, of which we have a tolerable knowledge, is that of insects,
among which we meet with peculiarities of a very remarkable kind, and such
as are found in no other island on the globe. Having already given a full
account of some of these peculiarities in a paper read before the Linnean
Society--republished in my _Contributions to the Theory of Natural
Selection_,--while others have been discussed in my _Geographical
Distribution of Animals_ (Vol. I. p. 434)--I will only here briefly refer
to them in order to see whether they accord with, or receive any
explanation from, the somewhat novel view of the past history of the island
here advanced.

The general distribution of the two best known groups of insects--the
butterflies and the beetles--agrees very closely with that of the birds and
mammalia, inasmuch as Celebes forms the eastern limit of a number of
Asiatic and Malayan genera, and at the same time the western limit of
several Moluccan and Australian genera, the former perhaps preponderating
as in the higher animals.

_Himalayan Types of Birds and Butterflies in Celebes._--A curious fact of
distribution exhibited both among butterflies and birds, is the occurrence
in Celebes of species and genera u