278 METAMORPHOSES OF MAN 



general among the members of the other sub-king- 

 dom, and in these it is more complete the lower we 

 go. There is an immense difference between the 

 caterpillar (the butterfly' s larva) and the little ciliated 

 creature which is the larva of the Hermella. The 

 former is a very complex animal, which performs 

 important functions; the latter is, so to speak, only 

 a vitellus, enclosed in its blastoderm, and clothed 

 with cilia. It is because the caterpillar belongs to a 

 superior, and the ciliated larva to an inferior member 

 of the same sub-kingdom. 



. Geneagenesis is controlled by the same law. Its 

 phases become more numerous and better defined, in 

 proportion as we descend in the scale of beings. It 

 is the exception among Articulata, but becomes the 

 rule among radiate animals. 



Proportionally as metamorphosis becomes complex, 

 it renders the naturalist's description of any species 

 less simple. 



Among animals which undergo transformation this 

 description is simple enough. The important modifi- 

 cations take place out of sight, and we have only to 

 sum up the features resulting from changes of the 

 external characters of the young beings, and the dis- 

 tinctions which exist between the male and female. 

 In animals with metamorphoses properly so called, the 

 difficulty is increased. In insects, one must be ac- 

 quainted with the larva, nymph and perfect animal, 

 of the latter of which there are always male and 

 female. In the Teredo one must be familiar with a 

 series of forms, which are quite as well marked, but 

 far more variable. Finally, in animals with geneagene- 

 sis, we must embrace the characters of four or five 



