348 INHABITANTS OF OCEANIC ISLANDS. [Chap. XIII. 



of the creation of each separate species, will have to admit that 

 a sufficient number of the best adapted plants and animals were 

 not created for oceanic islands ; for man has unintentionally stocked 

 them far more fully and perfectly than did nature. 



Although in oceanic islands the species are few in number, the 

 proportion of endemic kinds (*. e. those found nowhere else in 

 the world) is often extremely large. If we compare, for instance, 

 the number of endemic land-shells in Madeira, or of endemic birds 

 in the Galapagos Archipelago, with the number found on any 

 continent, and tben compare the area of the island with that of 

 the continent, we shall see that this is true. This fact might 

 have been theoretically expected, for, as already explained, species 

 occasionally arriving after long intervals of time in a new and 

 isolated district, and having to compete with new associates, would 

 be eminently liable to modification, and would often produce groups 

 of modified descendants. But it by no means follows that, because 

 in an island nearly all the species of one class are peculiar, those of 

 another class, or of another section of the same class, are peculiar ; 

 and this difference seems to depend partly on the species which are 

 not modified having immigrated in a body, so that their mutual 

 relations have not been much disturbed ; and partly on the fre- 

 quent arrival of unmodified immigrants from the mother-country, 

 with which the insular forms have intercrossed. It should be 

 borne in mind that the offspring of such crosses would certainly 

 gain in vigour; so that even an occasional cross would produce 

 more effect than might have been anticipated. I will give a few 

 illustrations of the foregoing remarks : in the Galapagos Islands 

 there are 26 land-birds ; of these 21 (or perhaps 23) are peculiar, 

 whereas of the 11 marine birds only 2 are peculiar; and it is 

 obvious that marine birds could arrive at these islands much more 

 easily and frequently than land-birds. Bermuda, on the other 

 hand, which lies at about the same distance from North America 

 as the Galapagos Islands do from South America, and which has 

 a very peculiar soil, does not possess a single endemic land-bird ; 

 and we know from Mr. J. M. Jones's admirable account of Bermuda, 

 that very many North American birds occasionally or even fre- 

 quently visit this island. Almost every year, as I am informed 

 by Mr. E. V. Harcourt, many European and African birds are 

 blown to Madeira ; this island is inhabited by 99 kinds, of which 

 one alone is peculiar, though very closely related to a European 

 form; and three or four other species are confined to this island 

 and to the Canaries. So that the Islands of Bermuda and Madeira 

 have been stocked from the neighbouring continents with birds, 



