Animal Causes. 217 



have we a record of her progress, her successes, and 

 failures in almost every department of animal 

 mechanics, but in embryology and metamorphosis 

 we have demonstrative evidence also of her regress, 

 of higher forms incontinently discarded for lower. 

 This is conspicuous in the evolution of the barnacle, 

 as observed by Darwin, for the mature cirrepedia is 

 lower in the scale of organisation than its larva. The 

 larvae in the first stage have three pairs of legs, a very 

 simple single eye, and a probosciformed mouth with 

 which they feed largely. In the second stage, answer- 

 ing to the chrysalis stages of butterflies, they have six 

 pairs of beautifully constructed natatory legs, a pair 

 of magnificent compound eyes and extremely com- 

 plex antennas, but a closed and imperfect mouth 

 which prevents them feeding. In the third and last 

 stage their legs are converted into prehensile organs, 

 and they again obtain a well-constructed mouth, but 

 they have no antennae, and their two eyes are now 

 reconverted into a minute and very simple eye-spot.* 

 On no other hypothesis save that of accidental evolu- 

 tion could we account for such arbitrary, not to say 

 stupid, transformations. 



Again, when anatomists, botanists, and biologists 

 respectively assure us that the mammal skull is 

 formed of "metamorphosed vertebrae ; that the crab's 

 jaws are metamorphosed legs ; that the sepals, petals, 

 stamens, and pistils of a flower are metamorphosed 

 leaves arranged in a spire ; and that all the different 



* Origin of Species, p. 441. 



