COLLECTION OF RADIARIA. 



M. dc Lamarck, availing himself of the labours of 

 Peron on these animals, has divided them into 

 two orders, the soft radiaria and the echinoder- 

 rnata. Those of the first order have been divided 

 into two sections, the anomala and the medu- 

 saria. They have all gelatinous bodies. There 

 is a numerous series of them in the cabinet of 

 anatomy. Amongst those under our inspection 

 we shall point out in the first section the beroe 

 and the noctiluca, which are the principal cause 

 of the phosphorescence of the sea. The phy- 

 salia, a specimen of which, placed near the 

 echini, shows its internal and cartilaginous blad- 

 der. Persons who have travelled beyond the tro- 

 pics have been struck with the beautiful colours 

 of this animal, as well as with its form, which is 

 like the hull of a ship. In the second section 

 we remark the cephea rhizostoma, Peron, whose 

 gelatinous body, skirted with purple, is often 

 found on the shores of the English channel. 



The radiaria of the second order have a hard 

 and tough skin, frequently crustaceous ; they are 

 divided into three sections, the stelleridce, the 

 echmides and thejistulides. 



The stelleridcc or sea-stars have a flattened and 

 circular body, whence issue five principal rays 

 which are sometimes subdivided. These animals 

 feed on worms and small crustaccae. They pre- 



