s less
than 1,000 fathoms deep, while on each side it sinks rapidly to depths of
2,400 and 2,600 fathoms. We have therefore no reason to believe that they
have ever been connected with {435} Madagascar, and this view is strongly
supported by the character of their indigenous fauna. Of this, however, we
have not a very complete or accurate knowledge, for though both islands
have long been occupied by Europeans, the study of their natural products
was for a long time greatly neglected, and owing to the rapid spread of
sugar cultivation, the virgin forests, and with them no doubt many native
animals, have been almost wholly destroyed. There is, however, no good
evidence of there ever having been any indigenous mammals or amphibia,
though both are now found and are often recorded among the native
animals.[109]

The smaller and more remote island, Rodriguez, is also volcanic; but it
has, besides a good deal of coralline rock, an indication of partial
submergence helping to account for the poverty of its fauna and flora. It
stands on a 100-fathom bank of considerable extent, but beyond this the
{436} sea rapidly deepens to more than 2,000 fathoms, so that it is truly
oceanic like its larger sister isles.

_Birds._--The living birds of these islands are few in number and consist
mainly of peculiar species of Mascarene types, together with two peculiar
genera--Oxynotus belonging to the Campephagidae or caterpillar-catchers, a
family abundant in the old-world tropics; and a dove, Trocazza, forming a
peculiar sub-genus. The origin of these birds offers no difficulty, looking
at the position of the islands and of the surrounding shoals and islets.

_Extinct Birds._--These three islands are, however, preeminently remarkable
as having been the home of a group of large ground-birds, quite incapable
of flight, and altogether unlike anything found elsewhere on the globe; and
which, though once very abundant, have become totally extinct within the
last two hundred years. The best known of these birds is the dodo, which
inhabited Mauritius; while allied species certainly lived in Bourbon and
Rodriguez, abundant remains of the species of the latter island--the
"solitaire," having been discovered, corresponding with the figure and
description given of it by Legouat, who resided in Rodriguez in 1692. These
birds constitute a distinct family, Dididae, allied to the pigeons but very
isolated. They were quite defenceless, and were rapidly ext