326 INHABITANTS OF OCEANIC ISLANDS. [CHAP. XIII. 



On the Inhabitants of Oceanic Islands. 



We now come to the last of the three classes of facts, which I 

 have selected as presenting the greatest amount of difficulty with 

 respect to distribution, on the view that not only all the indi- 

 viduals of the same species have migrated from some one area, but 

 that allied species, although now inhabiting the most distant 

 points, have proceeded from a single area, the birthplace of their 

 early progenitors. I have already given my reasons for disbeliev- 

 ing in continental extensions within the period of existing species, 

 on so enormous a scale that all the many islands of the several 

 oceans were thus stocked with their present terrestrial inhabitants. 

 This view removes many difficulties, but it does not accord with 

 all the facts in regard to the productions of islands. In the follow- 

 ing remarks I shall not confine myself to the mere question of 

 dispersal, but shall consider some other cases bearing on the truth 

 of the two theories of independent creation and of descent with 

 modification. 



The species of all kinds which inhabit oceanic islands are few in 

 number compared with those on equal continental areas : Alph. de 

 Candolle admits this for plants, and Wollaston for insects. New 

 Zealand, for instance, with its lofty mountains and diversified 

 stations, extending over 780 miles of latitude, together with the 

 outlying islands of Auckland, Campbell and Chatham, contain 

 altogether only 960 kinds of flowering plants ; if we compare this 

 moderate number with the species which swarm over equal areas 

 in South- Western Australia or at the Cape of Good Hope, we 

 must admit that some cause, independently of different physical 

 conditions, has given rise to so great a difference in number. Even 

 the uniform county of Cambridge has 847 plants, and the little 

 island of Anglesea 764, but a few ferns and a few introduced plants 

 are included in these numbers, and the comparison in some other 

 respects is not quite fair. We have evidence that the barren island 

 of Ascension aboriginally possessed less than half-a-dozen flower- 

 ing plants ; yet many species have now become naturalised on it, 

 as they have in New Zealand and on every other oceanic island 

 which can be named. In St. Helena there is reason to believe that 

 the naturalised plants and animals have nearly or quite extermi- 

 nated 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 



