ACALEPH^E. 65 



the entire surface of the sea. All however are not equally minute, 

 some grow to a large size ; and their forms are familiar to the inha- 

 bitants of every beach, upon which, when cast up by the waves, 

 they lie like masses of gelly, melting as it were in the sun, inca- 

 pable of motion and exhibiting few traces of organization, or 

 indications of that elaborate structure which more careful examina- 

 tion discovers them to possess. Their uncouth appearance has 

 obtained for them various appellations by which they are fami- 

 liarly known, as sea-gelly, sea-blubber, or gelly- fishes; whilst, 

 from disagreeable sensations produced by handling most of them, 

 they have been called sea-nettles, stingers, or stang-fishes. The 

 faculty of stinging is indeed the most prominent feature in their 

 history, so that their names in almost all languages are derived 

 from this circumstance : they were known to the older naturalists 

 by the title of Urtica marina ; and the word at the head of this 

 chapter, applied by Cuvier to the entire class, and originally used 

 by Aristotle, is of similar import (axaXrjpij, a nettle). 



There are few subjects which come under the observation 

 of the physiologist more calculated to excite his astonishment 

 than the history of these creatures. If he considers, in the first 

 place, the composition of their bodies, what does he find ? -an 

 animated mass of sea-water, for such in an almost literal sense 

 they are. Let him take a medusa of any size, and lay it in a 

 dry place ; it will be found gradually to drain away, leaving nothing 

 behind but a small quantity of transparent cellular matter, almost 

 as delicate as a cobweb, which apparently formed all the solid 

 frame-work of the body, and which, in an animal weighing five or 

 six pounds, will scarcely amount to as many grains ; and even if 

 the water which has escaped from this cellulosity be collected and 

 examined, it will be found to differ in no sensible degree from the 

 element in which the creature lived. The conclusion therefore 

 at which he naturally arrives is, that, in the medusae, the sea-water 

 collected and deposited in the delicate cells of an almost imper- 

 ceptible film becomes in some inscrutable manner instrumental 

 to the exercise of the extraordinary functions with which these 

 creatures are endowed. The Acalephse have been divided by 

 zoologists into groups distinguished by the nature of their means 

 of progression : in describing therefore the organs of locomotion, 

 with which we commence their history, the reader will be made 

 acquainted with the principal modifications of outward fonn which 

 they exhibit. 



