EVIDENCES FROM GEOGRAPHIC DISTRIBUTION 107 



more restricted range, and therefore the least likely to have found 

 their way to the islands with any frequency. 



The insect fauna of the Galapagos Islands is scanty, and chiefly 

 composed of beetles. These number 35 species, which are nearly all 

 peculiar, and in some cases go to constitute peculiar genera. The 

 same remarks apply to the twenty species of land-shells. Lastly, of 

 the total number of flowering plants (332 species) more than one 

 half (174 species) are peculiar. It is observable in the case of 

 these peculiar species of plants as also of the peculiar species of 

 birds that many of them are restricted to single islands. It is also 

 observable that with regard both to the fauna and flora, the Galapagos 

 Islands as a whole are very much richer in peculiar species than either 

 the Azores or Bermudas, notwithstanding that both the latter are 

 considerably more remote from the nearest continents. This differ- 

 ence, which at first sight appears to make against the evolutionary 

 interpretation, really tends to confirm it. For the Galapagos Islands 

 are situated in a calm region of the globe, unvisited by those periodic 

 storms and hurricanes which sweep over the North Atlantic, and which 

 every year convey some straggling birds, insects, seeds, etc., to the 

 Azores and Bermudas. Notwithstanding their somewhat greater 

 isolation geographically, therefore, the Azores and Bermudas are 

 really less isolated biologically than are the Galapagos Islands; and 

 hence the less degree of peculiarity on the part of their endemic 

 species. But, on the theory of special creation, it is impossible to 

 understand why there should be any such correlation between the 

 prevalence of gales and a comparative inertness of creative activity. 

 And, as we have seen, it is equally impossible on this theory to under- 

 stand why there should be a further correlation between the degree 

 of peculiarity on the part of the isolated species, and the degree in 

 which their nearest allies on the mainland are there confined to narrow 

 ranges, and therefore less likely to keep up any biological communi- 

 cation with the islands. 



St. Helena. A small volcanic island, ten miles long by eight 

 wide, situated in mid-ocean, 1,100 miles from Africa, and 1,800 from 

 South America. It is very mountainous and rugged, bounded for the 

 most part by precipices, rising from ocean depths of 17,000 feet, to a 

 height above the sea-level of nearly 3,000. When first discovered it 

 was richly clothed with forests; but these were all destroyed by human 

 agency during the 1 6 th, 1 7 th, and 1 8th centuries. The records of civili- 

 zation present no more lamentable instance of this kind of destruction. 



