172 ORGANIC EVOLUTION CONSIDERED 



If a deposit of pigment is the beginning of the evolu- 

 tion of eyes, it would seem that the entire surface of 

 the skin of the Negro is making a desperate effort to 

 evolve eyes, especially, since everywhere in this pig- 

 ment nerve fibres have their terminations. 



As to location of eyes, we find that all animals 

 which possess a fore-and-aft structure have the eyes 

 on the front part of the body. If the eyes of snails, 

 cuttle-fishes, the simple and compound eyes of in- 

 sects, the compound eyes of crustaceans, the single 

 eye of Nauplii, the eyes of spiders, centipedes and 

 niyriapods, and the eyes of vertebrates have all had 

 separate origins, it is very strange that according to 

 the above theory they should all be located in the 

 head. The origin of eyes from pigment "deposited 

 in points and patches, as it were by accident," will do 

 very well to locate eye-spots which are found in 

 various positions on animals, but it totally fails to 

 locate the kinds of eyes found in the head, which 

 had separate origins. It is said that lightning never 

 strikes twice in the same place, but the accidental 

 pigment spots giving origin to eyes occurred many 

 times on the heads of different animals. That they 

 should occur in this place and nowhere else in these 

 various animals, is indeed marvelous. If it is claimed 

 that these various eyes located in the head were all 

 evolved from the eyes of some one original form, we 

 answer that, as already shown, it is manifestly impos- 

 sible. According to this pigment-spot theory, eyes 

 are not necessarily located in the best places on the 

 body, as we find them to be, but they would be 

 evolved in any place where they would be of use. It 

 is evident that eyes located in almost any part of the 

 body would be better than no eyes. Nor would their 

 evolution be confined to any particular time in the 

 history of a species. If Spencer's theory of "the 



