76 KTENINGS AT THE MICEOSCOPE. 



a Sea-urchin are covered witli a thin fihn of living 

 flesh. 



The functions and use of these singular processes 

 are as obscure as their connexions with the animal. 

 Yet that they play some important part we may almost 

 certainly infer, from the general prevalence of similar 

 or analogous appendages among the various forms of 

 this class. The globular pearls which you lately saw 

 on the sea-mat, is but another form of bird's head ; and 

 the falling-door answers to the opening and shutting 

 mandible. The forms, indeed, of these organs are very 

 diverse, and sometimes they are greatly disguised. But 

 what about their function ? More than one observer 

 has noticed the seizure of small roving animals by these 

 pincer-like beaks ; and hence the conclusion is pretty 

 general, that they are in some way connected with the 

 procuring of food. But it seems to have been forgotten, 

 not only that these organs have no power of passing the 

 prey thus seized to the mouth, but also that this latter 

 is situated at the bottom of a funnel of ciliated tenta- 

 cles, and is calculated to receive only such minute prey 

 as is drawn within the ciliary vortex. I have ventured 

 to suggest a new explanation. The seizure of a passing 

 animal, and the holding of it in a tenacious grasp until 

 it dies, may be a means of attracting the proper prey to 

 the vicinity of the mouth. The presence of decom- 

 posing animal substance in water invariably attracts 

 crowds of infusory animalcules, which then breed with 

 amazing rapidity, so as to form a cloud of living atoms 

 around the decaying body, quite visible in the aggre- 

 gate to the lanassisted eye ; and these remain in the 

 vicinity, playing round and round until the organic 

 matter is quite consumed. Now a tiny Annelid or 



