244 PHOLADES AT HOME. 



manifested in the small piece of stone alluded to in 

 no less than four instances. Here let me observe, 

 that it is not always the larger mollusc that bores 

 through the smaller one ; it as frequently happens 

 that the latter deserves the brand of wanton aggressor. 

 Both cases are common enough, and, indeed, must of 

 necessity occur, wherever at any time a colony of 

 various sized Pholades are clustered together in a 

 small portion of rock. 



A fragment of rock riddled by the Pholas is a 

 much more pleasing sight than can be witnessed at 

 the sea shore in connection with that animal under 

 usual circumstances. For this reason : When visiting 

 the habitat of the boring bivalves, a host of small 

 circular holes are sometimes seen ; at other times the 

 surface of the same portion of the beach appears 

 comparatively sound, and it is only by striking a 

 smart blow with a hammer upon the ground, that 

 we render scores of orifices instantly observable in 

 all directions, from each of which is thrown a small 

 ; et of water. This phenomenon is caused by the 

 Pholades in alarm retracting their siphons, which had 

 hitherto filled the entire extent of the tunnels. At 

 such a locality, if a piece of rock be excavated, various 

 specimens of these boring molluscs, shrunk to their 

 smallest possible size, will be discovered at the base 

 of the cavities, which are invariably of a conical 

 form, tapered at the top, arid gradually enlarging as 

 they descend. 



