68 BIOLOGICAL LECTURES. 



with Captain Du Petit Thouars, stopped at the islands from the 

 2ist of June to the i5th of July ; in 1852 we find the Swedish 

 ship " Eugenie " there, with Dr. Kinberg, the zoologist and Dr. 

 Anderssen, the botanist ; then follows the English ship " Her- 

 ald," January 6-16, 1846 ; Dr. Habel from New York, July 22, 

 i868-January i, 1869; the Hassler Expedition under Professor 

 L. Agassiz, June 10-19, 1870; the United States Fish Com- 

 mission steamer "Albatross," April 4-16, 1888; and again 

 with Professor A. Agassiz, March 28-April 4, 1891 ; the late 

 Mr. C. F. Adams and myself, June lO-September 6, 1891. l 



It was David Porter, the well-known commodore of the 

 United States frigate "Essex," who for the first time stated 

 (1815) that the different islands of the group contained differ- 

 ent races of the gigantic land-tortoises : the same statement is 

 made by Darwin, who says that the colonists on Charles Island 

 were able to tell from the aspect of a tortoise from which 

 special island it came. Similar results were reached by the 

 study of the birds and the flora. These are the words of 

 Darwin : 2 



" I have not as yet noticed by far the most remarkable 

 feature in the natural history of this archipelago ; it is, that 

 the different 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 state- 

 ment, and I had already partially mingled together the collec- 

 tions from two of the islands. I never 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 dis- 

 cover what is most interesting in any locality, than they are 



1 An account of this expedition is given by me in the BioL Centralbl., vol. 

 XII, 1892, pp. 221-250. 



2 Darwin, Charles: A Naturalist's Voyage, London, 1845. 



