178 METAMORPHOSES OP MAN 



Kolliker,* (xegen.baur,f and Vogt ;J and by our own 

 researches also.§ 



Hence we should expect to find the different forms 

 of reproduction, before described, occurring among the 

 Siphonophora; and such in fact is shown to be the 

 case, by the series of investigations we have just 

 referred to. There we observe geneagenesis in its 

 most complete and varied forms. Yet its final term 

 is almost always a medusiform animal, sometimes 

 long-lived, sometimes short, with an organization 

 frequently of a very simple character, but occasionally 

 more complex; in some instances free and floating, 

 as in the Aurelia, in others fixed, as in the case of 

 Lowen's Campanularia, and which alone assumes the 

 sexual attributes, male and female, and reproduces 

 itself by ova. We conceive it to be useless to intro- 

 duce the analogy we have so often employed, and to 

 contrast that which occurs among the Siphonophora 

 with the simple metamorphoses of the Lepidoptera. 



Looking at this multiplicity of phenomena, all 

 coming within the same scheme, one might feel 

 inclined to believe that geneagenesis, in spite of all 

 the complications to which it is liable, is a general 

 law for all the groups we have named ; that all polyps 

 spring from a medusa, and all medusas originate in 

 polyps which have reached their final condition of 

 development. But — and we cannot repeat it too 



* " Die Schwimpolypen oder Siphonophoren von Messina," 

 1853. 



t " Beitrage zur nahren Kenntniss der Schwimpolypen," 1854. 



J " Recherches sur les Animaux inferieurs de la Mediterranee," 

 first memoir, on the Siphonophora of the Sea of Nice, 1854. 



§ " Memorre sur l'Organisation des Physalies." — Annates des 

 Sciences naturelles, 1854. 



