Chap. XII. 
OCEANIC ISLANDS. 
389 
have selected as presenting the greatest amount of 
difficulty, on the view that all the individuals both of 
the same and of allied species have descended from a 
single parent; and therefore have all proceeded from a 
common birthplace, notwithstanding that in the course 
of time they have come to inhabit distant points of the 
globe. I have already stated that I cannot honestly 
admit Forbes’s view on continental extensions, which^ 
if legitimately followed out, would lead to the belief 
that within the recent period all existing islands have 
been nearly or quite joined to some continent. This view 
would remove many difficulties, but it would not, I 
think, explain all the facts in regard to insular produc¬ 
tions. In the following remarks I shall not confine 
myself to the mere question of dispersal; but shall 
consider some other facts, which bear on the truth of 
the two theories of independent creation and of descent 
with modification. 
The species of all kinds which inhabit oceanic islands 
are few in number compared with those on equal conti¬ 
nental areas: Alph. de Candolle admits this for plants, 
and Wollaston for insects. If we look to the large 
size and varied stations of New Zealand, extending over 
780 miles of latitude, and compare its flowering plants, 
only 750 in number, with those on an equal area at 
the Cape of Good Hope or in Australia, we must, I 
think, admit that something 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 com 
parison in some other respects is not quite fair. We 
have evidence that the barren island of Ascension ab¬ 
originally possessed under half-a-dozen flowering plants; 
