412 



INSULAR FLOEAS AND FAUNAS WITH 



[Ch. XLT. 



species visit the Bermndas at the distance of 600 miles from 

 the mainland."^ Mr. Darwin has therefore emphatically 

 dwelt on the absence of Mammalia in islands far from con- 

 tinents, as strongly confirmatory of his theory of the origin 

 of all species by descei 

 species. The absence of 



from pre-existing closely allied 



The absence of Mammalia also supplies ns with an 

 nment against the doctrine of continental extension. 



from Europe to the 



submerged 



remained 



certain volcanic mountains, the Mammalia would have re- 

 treated into such spots, for the smaller species at least might 

 have found subsistence there. It has been suggested by the 

 advocates of continental extension, that if Java should sink 

 down several thousand feet, no land would be left except the 

 summits of a series of lofty volcanic cones, round which 

 there would be everywhere a deep ocean. But these same 



them 



Mydaus 



Mammalia would take refug 



Had 



been able to swim to the Azores, Madeiras, or Canaries in the 

 Miocene epoch, there is no ground for supposing that their 

 descendants would not still survive; for, as before stated, each 

 island seems during its whole growth to have afforded a 

 habitable surface to terrestrial beinpfs. 



The rapid multiplication of goats when allowed to run 

 wild in St. Helena, and of both goats and dogs in Juan Fer- 

 nandez when introduced by the Spaniards, and of rabbits in 

 Porto SarJ:o, from a single brood imported there in 1418, 

 prove the fitness of small islands to maintain wild quadrupeds, 



m 



iwt 



has also been pointed out by Darwin, as a characteristic of 

 oceanic islands ; yet he remarks that frogs, when taken to 

 Madeira, the Azores, and Mauritius, have thriven to such a 



as to become a nuisance. If their spawn were 



degree 



carried down by a river to the sea, it would at once be de- 



^ Origin of Species, p. 469. 



