AND THE LOWER ANIMALS. 145 



CHAPTER XIV. 



DISCOVERY OE ALTERNATE GENERATION (sALPiE AND 

 MEDUSiE) . 



By combining the precise observations of Milne 

 Edwards with those of his predecessors and followers, 

 we are enabled to draw the following general con- 

 clusion : — The distribution of fixed animals is appa- 

 rently always due to the development of eggs pro- 

 duced by the female, and which are hatched at a 

 distance, giving rise, in most instances, to free and 

 active larvae. Here we observe both metamorphoses 

 properly so called, and the recurrent form to which we 

 referred elsewhere ; * besides, multiplication by buds 

 occurs in those individuals belonging to the social 

 group . 



This twofold method of propagation is evidently 

 necessary, and might suffice to ensure the existence 

 of polyps and other animals which live in colonies. 

 But organic nature, which is not limited to a single 

 or to the most simple path, had other surprises in 

 store for naturalists. In 1819, a Germanized French- 

 man — who must be admired by those who have 

 read M. Ampere's essay f — recorded a discovery, 

 which in novelty, and from the fact that it was un- 

 expected, was in no way inferior to those which pre- 



* Vide Chapter V. 



t "Kevue des deux Mondes," May 15, 1840. 

 L 



