Geographical Distribution. 235 



nc 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 ivherever 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. Moreover, 

 there is everywhere a constant correlation between 

 the degree of this peculiarity on the part of the fauna 

 and flora, and the time during which they have been 

 isolated. Thus, for instance, among the islands which 



