3/8 EVOLUTION, OLD AND NEW. 



as mainly due to disuse while above we find it mainly 

 due to natural selection I should say that immediately 

 after the word " islands " just quoted, Mr. Darwin adds 

 " and in this case natural selection will have aided in 

 reducing the organ, until it was rendered harmless and 

 rudimentary," but this is Mr. Darwin's manner, and 

 must go for what it is worth. 



How refreshing to turn to the simple straightforward 

 language of Lamarck. 



" Long continued disuse," he writes, " in conse- 

 quence of the habits which an animal has contracted, 

 gradually reduces an organ, and leads to its final 

 disappearance. . . . 



" Eyes placed in the head form an essential part of 

 that plan on which we observe all vertebrate organisms 

 to be constructed. Nevertheless the mole which uses 

 its vision very little, has eyes which are only very small 

 and hardly apparent. 



"The aspalax of Olivier, which lives underground 

 like the mole, and exposes itself even less than the 

 mole to the light of day, has wholly lost the use of 

 its sight, nor does it retain more than mere traces of 

 visual organs, these traces again being hidden under 

 the skin and under certain other parts which cover 

 them up and leave not even the smallest access to the 

 light. The Proteus, an aquatic reptile akin to the 

 Salamander and living in deep and obscure cavities 

 under water, has, like the aspalax, no longer anything 

 but traces of eyes remaining traces which are again 

 entirely hidden and covered up.* 



" The following consideration should be decisive. 



* 'Phil. Zool,,'tom. i. p. 242. 



