394 RADIATA. 



CLASS IV. ACALEPHA.* 



No one can have sailed over the ocean, or even 

 been in the habit of walking on its shores, without 

 observing numerous creatures of various sizes and 

 forms, but all bearing the appearance of an uniform 

 mass of clear jelly, having generally a visible con- 

 traction and dilatation, but very little of any other 

 voluntary motion. Many of them have certain long 

 strings, or fringed processes, hanging from them 

 as they float, which are found, when touched, to 

 communicate a severe smarting sensation to the 

 skin, similar to the sting of a nettle, but often far 

 more violent. From this property, and from their 

 texture, they are usually known by the names of 

 Sea-nettle, Sea-blubber, or Sea-jelly. The most 

 common form is that of a hemisphere, from six 

 inches to a foot in diameter, having a loose edge 

 or fringe, floating at the surface of the sea with 

 the convex side upwards ; while from the under 

 side depends a thick mass of wrinkled and fringed 

 organs, which probably serve as tentacles for the 

 procuring of food. The whole creature thus has 

 no slight resemblance to a large mushroom. These 

 may often be seen in great numbers in the Atlan- 

 tic, in all parts of it, and are often washed up on 

 the sea-beach, where, however, they soon entirely 



, a nettle. 



