280 



ISLAND LIFE. 



[part II. 



it is almost exclusively migratory birds that annually reach the 

 Azores and Bermuda; while the corresponding fact that the 

 seeds of those ]3lants, which are common to the Galapagos and the 

 adjacent continent, have all — as Sir Joseph Hooker states — some 

 special means of dispersal, is equally intelligible. The reason 

 why the Galapagos possess four times as many peculiar species 

 of plants as the Azores is clearly a result of the less constant 

 introduction of seeds, owing to the absence of storms ; the 

 greater antiquity of the group, allowing more time for specific 

 change ; and the influence of cold epochs and of alterations 

 of sea and land, in bringing somewhat different sets of plants at 

 different times within the influence of such modified winds and 

 currents as might convey them to the islands. 



On the whole, then, we have no difficulty in explaining the 

 probable origin of the flora and fauna of the Galapagos, by 

 means of the illustrative facts and general principles already 

 adduced. 



