356 THE ORIGIN OF SPECIES 



every other oceanic island which can be named. In St. Helena 

 there is reason to believe that the naturalized plants and animals 

 have nearly or quite exterminated many native productions. He 

 who admits the doctrine 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 (i. 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 then 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 occa- 

 sionally arriving, after long intervals of time, in the new and 

 isolated district, and having to compete with new associates, 

 would be eminently liable to modification, and would often pro- 

 duce 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 frequent 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 vigor; 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 twenty-six land birds; of these, twenty-one 

 (or perhaps twenty- three) are peculiar, whereas of the eleven 

 marine birds only two are peculiar; and it is obvious that marine 

 birds could arrive at those islands much more easily and fre- 

 quently than land birds. Bermuda, on the other hand, which lies 

 at about the same distance from North America as the Gala- 

 pagos 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' admirable account of Bermuda, that 

 very many North American birds occasionally or even frequently 

 visit this island. Almost every year, as I am informed by Mr. E. 

 Harcourt, many European and African birds are blown to Ma- 



