190 RELATIONS OF THE INHABITANTS OF [Chap. XttL 



so enormously remote, that the fact becomes an anomaly. 

 But this difficulty partially disappears on the view that 

 New Zealand, South America, and the other southern 

 lands have been stocked in part from a nearly inter- 

 mediate though distant point, namely from the antarctic 

 islands, "when they were clothed with vegetation, during 

 a warmer tertiary period, before the commencement of 

 the last Glacial period. The affinity, which though 

 feeble, I am assured by Dr. Hooker is real, between the 

 flora of the south-western corner of Australia and of the 

 Cape of Good Hope, is a far more remarkable case ; but 

 this affinity is confined to the plants, and will, no doubt, 

 some day be explained. 



The same law which has determined the relationship 

 between the inhabitants of islands and the nearest 

 mainland, is sometimes displayed on a small scale, but 

 in a most interesting manner, within the limits of the 

 same archipelago. Thus each separate island of the 

 Galapagos Archipelago is tenanted, and the fact is a 

 marvellous one, by many distinct species ; but these 

 species are related to each other in a very much closer 

 manner than to the inhabitants of the American con- 

 tinent, or of any other quarter of the world. This is 

 what might have been expected, for islands situated so 

 near to each other would almost necessarily receive 

 immigrants from the same original source, and from 

 each other. But how is it that many of the immigrants 

 have been differently modified, though only in a small 

 degree, in islands situated within sight of each other, 

 having the same geological nature, the same height, 

 climate, &c. ? This long appeared to me a great diffi- 

 culty : but it arises in chief part from the deeply-seated 

 error of considering the physical conditions of a country 



