GEOGRAPHICAL DISTRIBUTION 363 



universal rule that the endemic productions of islands are re- 

 lated to those of the nearest continent, or of the nearest large 

 island. The exceptions are few, and most of them can be ex- 

 plained. Thus, although Kerguelen Land stands nearer to Africa 

 than to America, the plants are related, and that very closely, 

 as we know from Dr. Hooker's account, to those of America: but 

 on the view that this island has been mainly stocked by seeds 

 brought with earth and stones on icebergs, drifted by the pre- 

 vailing currents, this anomaly disappears. New Zealand in its 

 endemic plants is much more closely related to Australia, the 

 nearest mainland, than to any other region: and this is what 

 might have been expected; but it is also plainly related to South 

 America, which, although the next nearest continent, is so enor- 

 mously remote, that the fact becomes an anomaly. But this diffi- 

 culty partially disappears on the view that New Zealand, South 

 America, and the other southern lands, have been stocked in part 

 from a nearly intermediate 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 comer 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 is- 

 land 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 continent, 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, the islands situated 

 within sight of each other, having the same geological nature, the 

 same height, climate, etc.? This long appeared to me a great 

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

 of considering the physical conditions of a country as the most 

 important; whereas it cannot be disputed that the nature of the 

 other species with which each has to compete, is at least as im- 



