Geographical Distribution. 235 
no less than 400 species which are all, without any 
exception, peculiar; while about three-quarters of 
them go to constitute peculiar genera. Again, of the 
plants, 620 species are believed to be endemic; and 
of these 377 are peculiar, yielding no less than 39 
peculiar genera. 
Prejudice apart, I think we must all now agree that 
it is needless to continue further this line of proof. I 
have chosen the smallest and most isolated islands 
for the purposes of our present argument, first 
because these furnish the most crucial kind of 
test, and next because they best admit of being dealt 
with in a short space. But, if necessary, a vast 
amount of additional material could be furnished, 
not only from other small oceanic islands, but still 
more from the largest islands of the world, such as 
Australia and New Zealand. However, after the 
detailed inventories which have now been given 
in the case of some of the smaller islands most 
remote from mainlands, we may well be prepared to 
accept it as a general law, that wherever there is 
evidence of land-areas having been for a long time 
separated from other land-areas, there we meet with 
a more or less extraordinary profusion of unique 
species, often running up into unique genera. And, 
in point of fact, so far as naturalists have hitherto 
been able to ascertain, there is no exception to this 
general law in any region of the globe. Morcover, 
there is everywhere a constant correlation between 
the degree of this peculiarity on the part of the fauna 
and flora, and the ¢cme during which they have been 
isolated. Thus, for instance, among the islands which 
