198 CURIOUS HOMES AND THEIR TENANTS. 



moUusk, and, issuing from between the valves of the 

 shell and fastened to rocks, etc., serves to anchor this 

 animal in its place. How the filaments are fastened 

 has, I believe, never been explained. The nest of 

 this intelligent pecten is formed of coralline shells and 

 sand cemented together. 



The pholas, another nest-building shell, besides 

 the ability it exhibits of working its way into solid 

 rock, in which it hollows out its habitation, has other 

 interesting properties. It is very good to eat, for one 

 thing, being esteemed a great delicacy in some parts 

 of the British Isles, either cooked or uncooked. Eng- 



The pholas in burrows which it has excavated in granite. 



lish people call it piddock, and the piddock fishery is 

 of no small account in their eyes. But that which 

 gives it the greatest luster in the eyes of the natural- 

 ist is its luminosity. 



ilany mollusca have more or less phosphorescence, 

 but none, so to speak, can hold a candle to the pholas. 



