COMMON OBJECTS OF THE SHORE. 325 



The largest kind of jelly-fish frequent in our 

 seas is the Great Sea-nettle (EMzostoma Cuvierii}, 

 the name of root-mouthed having been given to 

 the genus, because the animals composing it were, 

 until recently, believed to have no true mouth, but 

 to receive their nourishment from pores on the eight 

 large peduncles which hang from its centre. Like 

 the other Medusse, however, it is now thought to 

 have a true mouth. It is sometimes two feet in 

 diameter, and is several pounds in weight. Yet if 

 this large jelly-fish is left on the shore but a few 

 hours only, nothing remains of the mass but 

 a number of small films. The jelly of the living 

 animal is composed entirely of large cells of fra- 

 gile texture, arranged with exquisite regularity, 

 differing in form in the various species, and filled 

 with a fluid which seems to resemble sea-water. 

 In some species when this evaporates, nothing is 

 left but a stain on the stone where the jelly-fish 

 lay. This, as well as other species, has a great 

 sensibility to light, several of the smaller Medusae 

 being known to sink into deep water to avoid 

 a bright light. Though it seems doubtful if they 

 are gifted with eyes, they, like some other crea- 

 tures low in the scale of animal life, appear to be 

 endowed with senses, which give them perception 

 in a manner of which we can form no idea. A 

 writer on this subject records that he once saw 

 a shoal of the Great Sea-nettle of our coasts, 

 swimming high with the tide off Seaton, during 

 calm weather. As these animals approached the 

 boat, over whose side the writer was looking, they 

 gradually sank in the clear glassy sea, and it re- 

 quired some dexterity to catch, with the boat- 

 hook, only one or two of the great numbers which 



