CHAP. XI.] 



OCEANIC ISLANDS. 



237 



either themselves have reached them by crossing the ocean, or be 

 the descendants of ancestors who did so. Let us then see what 

 are, in fact, the animal and vegetable inhabitants of these islands, 

 and how far their presence can be accounted for. We will begin 

 with the Azores, or Western Islands, because they have been 

 thoroughly well explored by naturalists, and in their peculiarities 

 afford us an important clue to some of the most efficient means 

 of distribution among several classes of animals. 



