t has undergone, a
relic or substratum of the fauna and flora of some more ancient land has
been here preserved to us.

It is only since my return home, and since I have been able to compare
the productions of Celebes side by side with those of the surrounding
islands, that I have been fully impressed with their peculiarity, and
the great interest that attaches to them. The plants and the reptiles
are still almost unknown; and it is to be hoped that some enterprising
naturalist may soon devote himself to their study. The geology of the
country would also be well worth exploring, and its newer fossils would
be of especial interest as elucidating the changes which have led to its
present anomalous condition. This island stands, as it were, upon the
boundary-line between two worlds. On one side is that ancient Australian
fauna, which preserves to the present day the facies of an early
geological epoch; on the other is the rich and varied fauna of Asia,
which seems to contain, in every class and order, the most perfect and
highly organised animals. Celebes has relations to both, yet strictly
belongs to neither: it possesses characteristics which are altogether
its own; and I am convinced that no single island upon the globe would
so well repay a careful and detailed research into its past and present
history.

_Concluding Remarks._

In writing this essay it has been my object to show how much may, under
favourable circumstances, be learnt by the study of what may be termed
the external physiology of a small group of animals, inhabiting a
limited district. This branch of natural history had received little
attention till Mr. Darwin showed how important an adjunct it may become
towards a true interpretation of the history of organized beings, and
attracted towards it some small share of that research which had before
been almost exclusively devoted to internal structure and physiology.
The nature of species, the laws of variation, the mysterious influence
of locality on both form and colour, the phenomena of dimorphism and of
mimicry, the modifying influence of sex, the general laws of
geographical distribution, and the interpretation of past changes of the
earth's surface, have all been more or less fully illustrated by the
very limited group of the Malayan Papilionidae; while, at the same time,
the deductions drawn therefrom have been shown to be supported by
analogous facts, occurring in other and often widely-separat