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ISLAND LIFE 



PART II 



passage to them of various organisms would be greatly 

 facilitated. Sunken banks, the relics of such islands, are 

 known to exist in many parts of the ocean, and countless 

 others, no doubt, remain undiscovered. 



The Keeling Islands as Illustrating the Manner in which 

 Oceanic Islands are Peopled. — That such causes as have 

 been here adduced are those by which oceanic islands have 

 been peopled, is further shown by the condition of equally 

 remote islands which we know are of comparatively recent 

 origin. Such are the Keeling or Cocos Islands in the 

 Indian Ocean, 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 histor}^ 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. Reptiles 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 produced thirteen species belonging to 

 eight distinct orders. The only beetle was a small Elater, 

 the Orthoptera were a Gryllus 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 thsm to live and 

 multiply, in order to give these islands a fauna and flora 

 equal to that of the Bermudas. Of wild plants only 

 twenty species were found belonging to nineteen genera 



