and inadequate to explain the remaining portion.[103] Since that
time I have seen no attempt even to discuss the question on general grounds
in opposition to my views, nor on the other hand have those who have
hitherto supported the hypothesis taken any opportunity of acknowledging
its weakness and inutility. I have therefore here explained my reasons for
rejecting it somewhat more fully and in a more popular form, in the hope
that a check may thus be placed on the continued re-statement of this
unsound theory as if it were one of the accepted conclusions of modern
science.

{428}

_The Mascarene Islands._[104]--In the _Geographical Distribution of
Animals_, a summary is given of all that was known of the zoology of the
various islands near Madagascar, which to some extent partake of its
peculiarities, and with it form the Malagasy sub-region of the Ethiopian
region. As no great additions have since been made to our knowledge of the
fauna of these islands, and my object in this volume being more especially
to illustrate the mode of solving distributional problems by means of the
most suitable examples, I shall now confine myself to pointing out how far
the facts presented by these outlying islands support the views already
enunciated with regard to the origin of the Madagascar fauna.

_The Comoro Islands._--This group of islands is situated nearly midway
between the northern extremity of Madagascar and the coast of Africa. The
four chief islands vary between sixteen and forty miles in length, the
largest being 180 miles from the coast of Africa, while one or two smaller
islets are less than 100 miles from Madagascar. All are volcanic, Great
Comoro being an active volcano 8,500 feet high; and, as already stated,
they are situated on a submarine bank with less than 500 fathoms soundings,
connecting Madagascar with Africa. There is reason to believe, however,
that these islands are of comparatively recent origin, and that the bank
has been formed by matter ejected by the volcanoes or by upheaval. Anyhow,
there is no indication whatever of there having been here a land-connection
between Madagascar and Africa; while the islands themselves have been
mainly colonised from Madagascar, some of them making a near approach to
the 100-fathom bank which surrounds that island.

The Comoros contain two land mammals, a lemur and a civet, both of
Madagascar genera and the latter an identical species, and there is also a
peculiar sp