INHABITANTS OF OCEANIC ISLANDS 433 



mals were not created for oceanic islands; for man has unin- 

 tentionally 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 occasionally 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 produce groups of 

 modified descendants. But it by no means follows that, be- 

 cause 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 immi- 

 grated 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 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 arc 26 land-birds; of these 21 for 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 wo know 

 from Mr. J. M. Jones' admirable account of Bermuda, that 

 very many North American birds occasionally or even fre- 

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

 formed by Mr. E. V. Harcourt. many European and .Xfrican 



