CHAPTER XIII. GEOGRAPHICAL DISTRIBUTION--continued.
3. ABSENCE OF BATRACHIANS AND TERRESTRIAL MAMMALS ON OCEANIC ISLANDS.
With respect to the absence of whole orders of animals on oceanic islands,
Bory St. Vincent long ago remarked that Batrachians (frogs, toads, newts)
are never found on any of the many islands with which the great oceans are
studded. I have taken pains to verify this assertion, and have found it
true, with the exception of New Zealand, New Caledonia, the Andaman
Islands, and perhaps the Solomon Islands and the Seychelles. But I have
already remarked that it is doubtful whether New Zealand and New Caledonia
ought to be classed as oceanic islands; and this is still more doubtful
with respect to the Andaman and Solomon groups and the Seychelles. This
general absence of frogs, toads and newts on so many true oceanic islands
cannot be accounted for by their physical conditions; indeed it seems that
islands are peculiarly fitted for these animals; for frogs have been
introduced into Madeira, the Azores, and Mauritius, and have multiplied so
as to become a nuisance. But as these animals and their spawn are
immediately killed (with the exception, as far as known, of one Indian
species) by sea-water, there would be great difficulty in their transportal
across the sea, and therefore we can see why they do not exist on strictly
oceanic islands. But why, on the theory of creation, they should not have
been created there, it would be very difficult to explain.