Although New Zealand is here
spoken of as an oceanic island, it is in some degree doubtful whether it
should be so ranked; it is of large size, and is not separated from
Australia by a profoundly deep sea; from its geological character and the
direction of its mountain ranges, the Rev. W.B. Clarke has lately
maintained that this island, as well as New Caledonia, should be considered
as appurtenances of Australia. Turning to plants, Dr. Hooker has shown
that in the Galapagos Islands the proportional numbers of the different
orders are very different from what they are elsewhere. All such
differences in number, and the absence of certain whole groups of animals
and plants, are generally accounted for by supposed differences in the
physical conditions of the islands; but this explanation is not a little
doubtful. Facility of immigration seems to have been fully as important as
the nature of the conditions.
Many remarkable little facts could be given with respect to the inhabitants
of oceanic islands. For instance, in certain islands not tenanted by a
single mammal, some of the endemic plants have beautifully hooked seeds;
yet few relations are more manifest than that hooks serve for the
transportal of seeds in the wool or fur of quadrupeds. But a hooked seed
might be carried to an island by other means; and the plant then becoming
modified would form an endemic species, still retaining its hooks, which
would form a useless appendage, like the shrivelled wings under the
soldered wing-covers of many insular beetles.
Pages:
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649