SEA-MATS AND SHELLY CORALLINES 85 



which may be presumed not only to line, but also to cover 

 the strong cell; just as the strong envelope and spines of 

 a Sea-urchin are covered with a thin film of living flesh. 

 The functions and use of these singular processes are 

 as obscure as their connections 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 conclu- 

 sion 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 

 tentacles, and is calculated to receive only such minute 

 prey as is drawn within the ciliary vortex. I have vent- 

 ured to suggest a new explanation. The seizure of a pass- 

 ing animal, and the holding of it in a tenacious grasp un- 

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

 the vicinity of the mouth. The presence of decomposing 

 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 aggregate to the 

 unassisted eye; .and these remain in the vicinity, playing 

 round and round until the organic matter is quite con- 



