THE ORIGIN OF THE MARINE FAUNA. 179 



The evidence afforded by the Coelenterates is 

 not so potent. Several naturalists believe that 

 some free-swimming form of Jelly-fish was the 

 ancestor, and that the fixed Zoophyte was a 

 stage introduced into the life-history at a later 

 period in the evolution of the group. Others 

 believe that the Zoophyte-stage came first and 

 that the Jelly-fish was introduced, for the 

 purpose of distributing, over a wide area, the 

 eggs of the species. My own researches lead 

 me to incline towards the latter view, but I feel 

 that it is still far from being proved. 



A great deal more could be written upon this 

 fascinating speculation about the origin of Life 

 in the Sea. But it is still a speculation, and 

 all that can be done at present is to weigh the 

 evidence carefully and see in which way the 

 scale seems to point. If I have succeeded in 

 making clear to the general reader the nature 

 of the evidence we can use in judging this 

 question, and have indicated to him the direction 

 in which it seems to me to point, my task has 

 been accomplished. 



