POLYPES, 



tatingly pronounce them eves, and so they are considered 

 by some eminent physiologists. Others, however, con- 

 sider them to bear a closer analogy to our organs of hear- 

 ing, the crystalline globule (or otolithe) being, as it is 

 stated, capable of vibration within its vesicle. Whatever 

 they be, the same organs are found, in the same form, in 

 that class of animals just alluded to, the Jelly-fishes or 

 Medusae. 



The disk is endowed with an energetic power of con- 

 traction, by which the margin is diminished, exactly like 

 that of a Medusa in swimming ; and the tentacles have 

 also the power of individual motion, though in general 

 this is languid, their rapid napping being the effect of the 

 contraction and expansion of the disk just mentioned, pro- 

 ducing a quick involution and evolution of the margin, 

 and carrying the tentacles with it. Occasionally, how- 

 ever, all the tentacles are strongly brought together at 

 their tips, with a twitching, grasping action, like that ol 

 fingers, which is certainly independent of the disk. 



The phenomena, ot which an example has been given 

 in this paper, have almost as greatly startled the philo- 

 sophers of our age, as those connected with the reproduc- 

 tion of the Hydra astonished our ancestors a century ago, 

 As in the former case, they were disbelieved, denied, ridi- 

 culed, confirmed, believed, wondered at, and at length have 

 found a place among the recognised laws of organic life, 

 as the Law of the Alternation of Generations. When we 

 come to speak of the Medusas as a class, we shall have 

 occasion to revert to the topic again ; for the present we 

 may state, that the order described is found to prevai 

 among many species and genera of the marine Polypes 



