CHAP, xiu.] THE GALAPAGOS ISLANDS. 275 



we know are of comparatively recent origin. Such are the 

 Keehng or Cocos Islands in the Indian Ocerai, situated about 

 the same distance from Sumatra as the Galapagos from South 

 America, but mere coral reefs, supporting abundance of cocoa- 

 nut palms as their chief vegetation. These islands were visited 

 by Mr. Darwin, and their natural history carefully examined. 

 The only mammals are rats, brought by a wrecked vessel and 

 said by Mr. Waterhouse to be common English rats, ''but 

 smaller and more brightly coloured ; " so that we have here an 

 illustration of how soon a difference of race is established under 

 a constant and uniform difference of conditions. There are no 

 true land-birds, but there are snipes and rails, both apparently 

 common Malayan species. Keptiles are represented by one 

 small lizard, but no account of this is given in the Zoology of the 

 Voyage of the Beagle, and we may therefore conclude that it was 

 an introduced species. Of insects, careful collecting only pro- 

 duced thirteen species belonging to eight distinct orders. The 

 only bettle was a small Eiater, the Orthoptera were a Gryilus 

 and a Blatta ; and there were two flies, two ants, and two small 

 moths, one a Diopsea which swarms everywhere in the eastern 

 tropics in grassy places. All these insects were no doubt brought 

 either by winds, by floating timber (which reaches the islands 

 abundantly), or by clinging to the feathers of aquatic or wading 

 birds ; and we only require more time to introduce a greater 

 variety of species, and a better soil and more varied vegetation, 

 to enable them to live and multiply, in order to give these 

 islands a fauna and flora equal to that of the Bermudas. Of 

 wild plants there were only twenty species, belonging to nine- 

 teen genera and to no less than sixteen natural families, while 

 all were common tropical shore plants. These islands are thus 

 evidently stocked by waifs and strays brought by the winds and 

 waves ; but their scanty vegetation is mainly due to unfavourable 

 conditions — the barren coral rock and sand, of which they are 

 wholly composed, together with exposure to sea-air, being 

 suitable to a very limited number of species which soon mono- 

 polise the surface. With more variety of soil and aspect a 

 greater variety of plants would establish themselves, and these 

 would favour the preservation and increase of more insects, 



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