394 GALAPAGOS ARCHIPELAGO. [cHap. xv1l. 
islands to a considerable extent are inhabited by a different set 
of beings. My attention was first called to this fact by the Vice- 
Governor, Mr. Lawson, declaring that the tortoises differed from 
the different islands, and that he could with certainty tell from 
which island any one was brought. I did not for some time 
pay sufficient attention to this statement, and I had already par- 
tially mingled together the collections from two of the islands. 
Inever dreamed that islands, about fifty or sixty miles apart, and 
most of them in sight of each other, formed of precisely the same 
rocks, placed under a quite similar climate, rising to a nearly 
equal height, would have been differently tenanted ; but we shall 
soon see that this is the case. It is the fate of most voyagers, no 
sooner to discover what is most interesting in any locality, than 
they are hurried from it; but I ought, perhaps, to be thankful 
that I obtained sufficient enaterials to establish this most remark- 
able fact in the distribution of organic beings. 
The inhabitants, as I have said, state that they can distinguish 
the tortoises from the different islands; and that they differ not 
only in size, but in other characters. Captain Porter has de- 
scribed * those from Charles and from the nearest island to it, 
namely, Hood Island, as having their shells in front thick and 
turned up like a Spanish saddle, whilst the tortoises from James 
Island are rounder, blacker, and have a better taste when cooked. 
M. Bibron, moreover, informs me that he has seen what he con- 
siders two distinct species of tortoise from the Galapagos, but he 
does not know from whichislands. The specimens that I brought 
from three islands were young ones; and probably owing to this 
cause, neither Mr. Gray nor myself could find in them any specific 
differences. I have remarked that the marine Amblyrhynchus 
was larger at Albemarle Island than elsewhere; and M. Bibron 
informs me that he has seen two distinct aquatic species of this 
genus; so that the different islands probably have their repre- 
sentative species or races of the Amblyrhynchus, as well as of the 
tortoise. My attention was first thoroughly aroused, by compar- 
ing together the numerous specimens, shot by myself and several 
other parties on board, of the mocking-thrushes, when, to my 
astonishment, I discovered that all those from Charles Island 
* Voyage in the U. S. ship Essex, vol. i. p. 215. 
