DEGENERA TION. 37 



show the transformation of the NaupHus into the 

 young Barnacle. Its organs of touch and of sight 

 atrophy, its legs lose their locomotor function, and 

 are simply used for bringing floating particles to 

 the orifice of the stomach ; so that an eminent 

 naturalist has compared one of these animals to a 

 man standing on his head and kicking his food 

 into his mouth. 



Were it not for the recapitulative phases in the 

 development of the Barnacle, we may doubt whether 

 naturalists would ever have guessed that it was a 

 degenerate Crustacean. It was in fact for a long 

 time regarded as quite remote from them, and placed 

 among the snails and oysters ; its true nature was 

 only admitted when the young form was discovered. 



Other parasitic organisms, which exhibit extreme 

 degeneration as compared with their free-living rela- 

 tives, might be cited and figured in profusion, did our 

 limits permit. Very noteworthy are the degenerate 

 Spiders — the mites, leading to still more degenerate 

 forms, the Linguatulae. 



We have two of these represented in Figs. 1 1 

 and 12. The one (Fig. 11), as compared with a 

 spider is seen still to possess the eight walking legs. 



