ILLUSTRATIVE OF NATURAL SELECTION, 199 
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 eluci- 
dating the changes which have led to its present ano- 
malous 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 re- 
search 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 
