

JELLY-FISHES. 823 



four straight, slender, slightly divergent tentacles, which 

 grow straight upward to a considerable length. The whole 

 structure retains the rich purple hue of the original 

 gemmule. 



Beyond this point I have not pursued the history of the 

 little Turris from personal observation; nor am I aware 

 that any naturalist besides has studied the development 

 of this particular genus. But the history of other genera 

 is known ; and as the phenomena they exhibit are quite 

 parallel to those which I have been describing, so far as 

 these have been traced, we may fairly conclude that there 

 is the same parallelism in the subsequent stages. 



Assuming this, then, the little crimson stem with four 

 rays, a veritable polype, buds four more tentacles in the 

 interspaces, making the total number eight ; these in like 

 manner increase progressively to sixteen, thirty-two, and 

 sixty-four. It now possesses a close resemblance to the 

 Hydra of our ditches, only having more tentacles ; and, 

 like it, the Medusa-larva buds forth from its sides young 

 Hydra-like polypes, which take the form of their imme- 

 diate parent, fall off, attach themselves, bud forth more, and 

 so on. All these catch living prey with their tentacles, 

 swallow them with their mouths, and digest them with 

 their stomachs, exactly like real polypes, and thus produce 

 generation after generation of similar beings. 



Years may pass in this stage, during which numberless 

 polypes are formed. At length the original stock, or any 

 one of its descendants, takes on an important change. Its 

 body lengthens, and becomes cut as it were into a number 

 of rings, as if tied tightly round with thread, or like the 

 body of an Annelid. These segments become increasingly 

 distinct, until at length each is seen to be a shallow cup, 

 notched at its margin, and sitting in the concavity of the 



I one next below it. This structure is developed first in 

 those at the free extremity of the polype, and progressively 

 downward ; and the terminal cups are nearly free, rocking 



Y2 



