166 METAMORPHOSES OF MAN 



CHAPTER XVI. 



GENEAGENETIC PHENOMENA IN ANNULOSA AND 

 MOLLUSCA. 



Hitheeto I have been endeavouring to show how the 

 knowledge of geneagenetic phenomena was gradually 

 arrived at. It now remains for me to explain, or 

 rather to describe, how these apparently exceptional 

 phenomena are referable to the most general laws in 

 the scientific scheme. But, before touching on the 

 theoretical portion of my subject, it is necessary to 

 bring forward a certain number of examples, in order 

 to justify conclusions which are occasionally different 

 from those that some of my distinguished colleagues 

 have drawn from the same premises. These examples 

 are especially interesting. We find in them the defi- 

 nitive solution of perhaps the most debated question 

 which has ever engaged the attention of philosophers 

 and naturalists. 



It has been already seen that geneagenesis becomes 

 more and more complex as we pass from the Hydra to 

 the Aurelia, and since facts of a similar character 

 are multiplying and presenting peculiarities which 

 are every day assuming more varied features, it 

 becomes necessary for the purposes of study to 

 arrange them in certain groups. This is what has 

 been done by Van Beneden, who proposes to dis- 

 tribute them among five sections. We shall adopt 



