GEOGRAPHICAL DISTRIBUTION 197 



On the Relations of the Inhabitants of Islands to those of 



the nearest Mainland 



The most striking and important fact for us is the 

 affinity of the species which inhabit islands to those of 

 the nearest mainland, without being actually the same. 

 Numerous instances could be given. The Galapagos 

 Archipelago, situated under the equator, lies at tiae dis- 

 tance of between 500 and 600 miles from the shores 

 of South America. Here almost every product of the 

 land and of the water bears the -unmistakable stamp of 

 the American continent. There are twenty-six land- 

 birds; of these, twenty-one, or perhaps twenty-three, 

 are ranked as distinct species, and would commonly be 

 assumed to have been here created; yet the close affinity 

 of most of these birds to American species is manifest in 

 every character, in their habits, gestures, and tones of 

 voice. So it is with the other animals, and with a large 

 proportioja of the plants, as shown by Dr. Hooker in his 

 admirable Flora of this archipelago. The naturalist, look- 

 ing at the inhabitants of these volcanic islands in the 

 Pacific, distant several hundred miles from the continent, 

 feels that he is standing on American land. Why should 

 this be so? why should the species which are supposed 

 to have been created in the Galapagos Archipelago, and 

 nowhere else, bear so plainly the stamp of affinity to 

 those created in America? There is nothing in the con- 

 ditions of life, in the geological nature of the islands, in 

 their height or climate, or in the proportions in which 

 the several classes are associated together, which closely 

 resembles the conditions of the South American coast; 

 in fact, there is a considerable dissimilarity in all these 



