Contributions to the theory of natural selection. A series of essays ... By Alfred Russel Wallace ...

ILLUSTRATIVE OF NATURAL SELECTIO21. 195
Remarkable Peculiarities of tlhe Island of Celebes.
If we now pass to the next island (Celebes), separated from those last mentioned by a strait not wider
than that which divides them from each other, we
have a striking contrast; for with a total number
of species less than either Borneo or Java, no fewer
than eighteen are absolutely restricted to it. Further
east, the large islands of Ceram and New Guinea. have
only three species peculiar to each, and Timor has
five. We shall have to look, not to single islands,
but to whole groups, in order to obtain an amount
of individuality comparable with that of Celebes. For
example, the extensive group comprising the large
islands of Java, Borneo, and Sumatra, with the peninsula of MIalacca, possessing altogether 48 species, has
about 24, or just half, peculiar to it; the numerous
group of the Philippines possess 22 species, of which
17 are peculiar; the seven chief islands of the Moluccas
have 27, of which 12 are peculiar; and the whole
of the Papuan Islands, with an equal number of species,
have 17 peculiar. Comparable with the most isolated
of these groups is Celebes, with its 24 species, of
which the large proportion of 18 are peculiar. We
see, therefore, that the opinion I have elsewhere expressed, of the high degree of isolation and the remarkable distinctive features of this interesting island, is
fully borne out by the examination of this conspicuous family of insects. A single straggling island
with a few small satellites, it is zoologically of equal
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