EVIDENCES FROM GEOGRAPHIC DISTRIBUTION loi 



If the emironment in a region adjoining a range should change in a 

 favourable manner, the range might be extended at that point without 

 any alteration on the part of the animals. 



"The distribution of animals is inferred to be in harmony with this 

 method, which involves, it will be noted, the factors of migration, 

 evolution, physiological and morphological dependence upon the 

 environment, the diversity and changcableness of the earth's surface, 

 and extinction; and in this manner are explained the differences in 

 geographical position, differences in size of range, differences in the 

 continuity of range and the fact that ranges are at first continuous, 

 differences in physical and biological conditions which characterize 

 the ranges of different forms, and the geographical proximity of 

 apparently related forms." 



SOME OF THE MORE SIGNIFICANT FACTS ABOUT THE 

 DISTRIBUTION OF ANIMALS 



THE FAtJXA OF OCEAXIC ISLANDS' 



GEORGE JOHN ROMANES 



Tiu-ning now from aquatic organisms to terrestrial, the body of 

 facts from wliich to draw is so large, that I think the space at my dis- 

 posal may be best utilized by confining attention to a single division 

 of them — that, namely, which is furnished by the zoological study of 

 oceanic islands. 



In the comparatively limited — but in itself extensive — class of 

 facts thus presented, we have a particularly fair and cogent test as 

 between the alternative theories of evolution and creation. For 

 where we meet with a volcanic island, hundreds of miles from any 

 other land, and rising abruptly from an ocean of enormous depth, we 

 may be quite sure that such an island can never have formed part of a 

 now submerged continent. In other words, we may be quite sure that 

 it always has been what it now is — an oceanic peak, separated from all 

 other land by himdreds of miles of sea, and therefore an area supplied 

 by nature for the purpose, as it were, of testing the rival theories of 

 creation and evolution. For, let us ask, upon these tiny insular 

 specks of land what kind of life should we expect to find ? To this 

 question the theories of special creation and of gradual evolution 

 would agree in giving the same answer up to a certain point. For 

 both theories would agree in supposing that these islands would, at all 



' From G. J. Romanes, Dard'in and after Dard.nn (copyright 1892). Used by 

 special permission of The Open Court Publishing Company. 



