Narrative of the surveying voyages of his majesty's ships Adventure and Beagle (vol.3)

628 ADDENDA. having passed the night on these black and naked rocks, have awakened in the morning with a strong paroxysm of fever." Humboldt thinks that these cases may be explained by the eflfect produced on the body by the high temperature, which the black rocks, coated with a layer of the oxides of manganese and iron, retain during the night. But it appears to me that the relation is too remarkable to be thus explained, between this fact and those mentioned by Dr. Ferguson, in which the desiccation of nearly bare rock in Spain, and of a very thin bed of earth overlying dry coral-rock in the West Indies, has given rise to the most pestiferous exhalations. Page 461. The sixth bird, mentioned as an inhabitant of the Galapagos, Mr. Gould now finds is not like the rest, peculiar to these islands, but is a known North American species of Ammodramus. Page 405. I have given my reason for believing that the Testudo, inappropriately called Indicus, is an aboriginal species of the Galapagos. I now find {Kerr's Voyages, vol. X., p. 373) that as far back as 1708, Woods, Rogers, and Courtney, in their voyage round the world, speaking of the tortoises of these islands, say that it is the opinion of the Spaniards that there is no other in these seas, except at the Galapagos : it is, however, then added, that they are common in Brazil, — a mistake which may be attributed to two different species not having been distinguished. It has been said that the bones of Testudo Indicus were found in numbers in the Isle of France, with some fragments of those of the Dodo ; but M. Bibron one of the best authorities in Europe on reptiles — informs me that he has reason to believe that a second species has been confounded under this name. In the same page I remark that there is every reason for believing that several of the islands possess their own peculiar varieties or species of tortoise, but that my specimens were too small to decide this question. M. Bibron now informs me, that he has seen full-grown animals, brought from this Archipelago, which he considers undoubtedly to be distinct species. At p. 467, I have observed that the specimens of the AmUy- rhyncus cristatus — that extraordinary marine herbivorous lizard — were larger from Albemarle, than from any other island. In this case, also, M. Bibron tells me, he has seen what he considers two species of the aquatic Amblyrhyncus, besides the terrestrial species. Doubtless the several islands have their own representatives of the Amblyrhyncus, like