422 GALAPAGOS ARCHIPELAGO chap. 



Hence we have the truly wonderful fact, that in James 

 Island, of the thirty-eight Galapageian plants, or those found 

 in no other part of the world, thirty are exclusively confined 

 to this one island ; and in Albemarle Island, of the twenty-six 

 aboriginal Galapageian plants, twenty-two are confined to this 

 one island, that is, only four are at present known to grow in 

 the other islands of the archipelago ; and so on, as shown in 

 the above table, with the plants from Chatham and Charles 

 Islands. This fact will, perhaps, be rendered even more 

 striking, by giving a few illustrations : — thus, Scalesia, a 

 remarkable arborescent genus of the Compositae, is confined to 

 the archipelago : it has six species ; one from Chatham, one 

 from Albemarle, one from Charles Island, two from James 

 Island, and the sixth from one of the three latter islands, but 

 it is not known from which : not one of these six species grows 

 on any two islands. Again, Euphorbia, a mundane or widely 

 distributed genus, has here eight species, of which seven are 

 confined to the archipelago, and not one found on any two 

 islands : Acalypha and Borreria, both mundane genera, have 

 respectively six and seven species, none of which have the 

 same species on two islands, with the exception of one Borreria, 

 which does occur on two islands. The species of the Compositae 

 are particularly local ; and Dr. Hooker has furnished me with 

 several other most striking illustrations of the difference of the 

 species on the different islands. He remarks that this law of 

 distribution holds good both with those genera confined to the 

 archipelago, and those distributed in other quarters of the 

 world : in like manner we have seen that the different islands 

 have their proper species of the mundane genus of tortoise, and 

 of the widely distributed American genus of the mocking'- 

 thrush, as well as of two of the Galapageian sub-groups of 

 finches, and almost certainly of the Galapageian genus 

 Amblyrhynchus. 



The distribution of the tenants of this archipelago would 

 not be nearly so wonderful, if, for instance, one island had 

 a mocking-thrush, and a second island some other quite 

 distinct genus ; — if one island had its genus of lizard, and 

 a second island another distinct genus, or none whatever ; — 

 or if the different islands were inhabited, not by representative 

 species of the same genera of plants, but by totally different 



