ing quite independently of any
difference in physical conditions has caused so great a difference in
number. Even the uniform county of Cambridge has 847 plants, and the
little island of Anglesea 764, but a few ferns and a few introduced
plants are included in these numbers, and the comparison in some other
respects is not quite fair. We have evidence that the barren island of
Ascension aboriginally possessed under half-a-dozen flowering plants;
yet many have become naturalised on it, as they have on New Zealand and
on every other oceanic island which can be named. In St. Helena there is
reason to believe that the naturalised plants and animals have nearly or
quite exterminated many native productions. He who admits the doctrine
of the creation of each separate species, will have to admit, that a
sufficient number of the best adapted plants and animals have not been
created on oceanic islands; for man has unintentionally stocked them
from various sources far more fully and perfectly than has nature.

Although in oceanic islands the number of kinds of inhabitants is
scanty, the proportion of endemic species (i.e. those found nowhere else
in the world) is often extremely large. If we compare, for instance, the
number of the endemic land-shells in Madeira, or of the endemic birds in
the Galapagos Archipelago, with the number found on any continent, and
then compare the area of the islands with that of the continent, we
shall see that this is true. This fact might have been expected on my
theory, for, as already explained, species occasionally arriving after
long intervals in a new and isolated district, and having to compete
with new associates, will be eminently liable to modification, and
will often produce groups of modified descendants. But it by no means
follows, that, because in an island nearly all the species of one class
are peculiar, those of another class, or of another section of the same
class, are peculiar; and this difference seems to depend on the species
which do not become modified having immigrated with facility and in a
body, so that their mutual relations have not been much disturbed. Thus
in the Galapagos Islands nearly every land-bird, but only two out of the
eleven marine birds, are peculiar; and it is obvious that marine birds
could arrive at these islands more easily than land-birds. Bermuda, on
the other hand, which lies at about the same distance from North America
as the Galapagos Islands do fro