The Origin of Species 



on islands far distant from any continent. Such 

 cases as the presence of peculiar species of bats 

 on oceanic islands and the absence of all other 

 terrestrial mammals, are facts utterly inexpli- 

 cable on the theory of independent acts of crea- 

 tion. 



The existence of closely allied representative 

 species in any two areas, implies on the theory of 

 descent with modification, that the same parent- 

 forms formerly inhabited both areas: and we 

 almost invariably find that wherever many 

 closely allied species inhabit two areas, some 

 identical species are still common to both. 

 Wherever many closely allied yet distant species 

 occur, doubtful forms and varieties belonging 

 to the same groups likewise occur. It is a rule of 

 high generality that the inhabitants of each area 

 are related to the inhabitants of the nearest 

 source whence immigrants might have been 

 derived. We see this in the striking relation 

 of nearly all the plants and animals of the Gala- 

 pagos Archipelago, of Juan Fernandez, and of 

 the other American islands, to the plants and 

 animals of the neighbouring American mainland ; 

 and of those of the Cape Verde Archipelago, and 

 of the other African islands to the African main- 

 land. It must be admitted that these facts re- 

 ceive no explanation on the theory of creation. 

 The fact, as we have seen, that all past and 

 present organic beings can be arranged within a 

 few great classes, in groups subordinate to groups, 

 and with the extinct groups often falling in be- 

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