RADIATA. 





Hydra. 



Polybrackionia Linnaeana.. a Upper side, b Lower side. 



Prafflf ul r<>n>ita clandifen 



The Rataria Mitrata has a circular, or oval body, supported by a subeartilaginous, compressed, elevated 

 piece, with a muscular, moveable, longitudinal crest above, concave beneath, and in the middle furnished 

 with a proboscis-shaped stomach, as also with one row of marginal, feeler-shaped suckers. 



The Porpita Gigantea has a regular, circular, membranous body, depressed and slightly convex above; 

 an internal cartilaginous support, circular, with its surface marked by concentric striae, crossing radiata 

 striae, and on its superior surface covered by a delicate membrane merely. Beneath, the body is concave, 

 and the under surface is supplied with numerous feelers, the outer ones being longest, and furnished with 

 small fringes, each terminated by a globule. These globules sometimes contain air, and the inner ones are 

 the shortest, simplest, and most fleshy. In the centre of these feelers is the mouth, formed like a small 

 proboscis, and leading to a simple stomach, surrounded by a glandular substance. It is found in nearly all 

 the seas. 



The Porpita Glandifera, in its leading characteristics, so closely resembles the Porpita Gigantea that no 

 separate verbal description is required, and we therefore refer the reader to the appended plate. 



In the Polybrachionia Linnreana, the back-support is cartilaginous, naked, flattened, rounded, radiated 

 and concentrically striated ; the mantle is narrow, and surrounds this support; the arms are numerous, 

 parallel, of different lengths, elongated, attached beneath, and capable of assuming a slanting position for 



Luiiuiites Radiate 



&1( dusa. 



PllY 



