18.35.] DISTRIBUTION OF THE ORGANIC BEINGS. 397 



islands. He remarks that this law of distribution holds good 

 both with those genera confined to the archipelago, and those dis- 

 tributed 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 Ame- 

 rican genus of the mocking-thrush, as well as of two of the Ga- 

 lapageian 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 mock- 

 ing-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 diffierent 

 islands were inhabited, not by representative species of the same 

 genera of plants, but by totally different genera, as does to a cer- 

 tain extent hold good ; for, to give one instance, a large berry- 

 bearing tree at James Island has no representative species in 

 Charles Island. But it is the circumstance, that several of the 

 islands possess their own species of the tortoise, mocking-thrush, 

 finches, and numerous plants, these species having the same 

 general habits, occupying analogous situations, and obviously 

 filling the same place in the natural economy of this archipelago, 

 that strikes me with wonder. It may be suspected that some of 

 these representative species, at least in the case of the tor- 

 toise and of some of the birds, may hereafter prove to be only 

 well-marked races ; but this would be of equally great interest 

 to the philosophical naturalist. I have said that most of the 

 islands are in sight of each other : I may specify that Charles 

 Island is fifty miles from the nearest part of Chatham Island, and 

 thirty-three miles from tlie nearest part of Albemarle Island. 

 Chatham Island is sixty miles from the nearest part of James 

 Island, but there are two intermediate islands between them 

 which were not visited by me. James Island is only ten miles 

 from the nearest part of Albemarle Island, but the two points 

 where the collections were made are thirty-two miles apart. I 

 must repeat, that neither the nature of the soil, nor height of the 

 land, nor the climate, nor the general character of the associated 

 beings, and therefore their action one on another, can differ much 

 in the different islands. If there be any sensible difference in 



