ve already shown in our fifth chapter, the
testimony of geology itself, if fairly interpreted, upholds the same theory
of the stability of our continents and the permanence of our oceans. Yet so
easy and pleasant is it to speculate on former changes of land and sea with
which to cut the gordian knot offered by anomalies of distribution, that we
still continually meet with suggestions of former continents stretching in
every direction across the deepest oceans, in order to explain the presence
in remote parts of the globe of the same genera even of plants or of
insects--organisms which possess such exceptional facilities both for
terrestrial, aerial, and oceanic transport, and of whose distribution in
early geological periods we generally know little or nothing.

_The Birds of Madagascar, as Indicating a Supposed Lemurian
Continent._--Having thus shown how the distribution of the land mammalia
and reptiles of Madagascar may be well explained by the supposition of a
union with Africa before the greater part of its existing fauna had reached
it, we have now to consider whether, as some ornithologists think, the
distribution and affinities of the birds present an insuperable objection
to this view, and require the adoption of a hypothetical
continent--Lemuria--extending from Madagascar to Ceylon and the Malay
Islands.

There are about one hundred and fifty land birds known from the island of
Madagascar, of which a hundred and twenty-seven are peculiar; and about
half of these peculiar species belong to peculiar genera, many of which are
extremely isolated, so that it is often difficult to class them in any of
the recognised families, or to determine their affinities to any living
birds.[100] Among the other moiety, {423} belonging to known genera, we
find fifteen which have undoubted African affinities, while five or six are
as decidedly Oriental, the genera or nearest allied species being found in
India or the Malay Islands. It is on the presence of these peculiar Indian
types that Dr. Hartlaub, in his recent work on the _Birds of Madagascar and
the Adjacent Islands_, lays great stress, as proving the former existence
of "Lemuria"; while he considers the absence of such peculiar African
families as the plantain-eaters, glossy-starlings, ox-peckers, barbets,
honey-guides, hornbills, and bustards--besides a host of peculiar African
genera--as sufficiently disproving the statement in my _Geographical
Distribution of Animals_