102 PHOLADID^. 



rally supposed. The cpcoXU of Aristotle was a kind of 

 fish, which he classes with the mullet ; and the (£&>\a? 

 of other Greek writers appears to have been Litliophaga 

 dactylus, which is certainly the Pholas of Rondeletius 

 and Aldrovandus. Our species of Pholas are the " Pid- 

 docks " of old English naturalists, and the " Pitaux '* or 

 " Dails " of the French. Mr. W. Wood remarks that 

 on the coast of Normandy they are eaten in abundance, 

 well seasoned and cooked with bread-crumbs and fine 

 herbs. They are also reckoned a delicacy when pickled 

 in vinegar. In the neighbourhood of Dieppe a great 

 many women and children, each provided with an iron 

 pick, are employed in collecting them, either to sell in 

 the market, or for fishermen's bait. They are almost 

 entirely littoral, 



" Entomb' d upon the very hem o' the sea." 



The property which they possess of shining in the dark 

 is very remarkable. It was mentioned by Reaumur in 

 the Mem. de l'Acad. Roy. for 1723; and his communi- 

 cation, "Des Merveilles des Dails, ou de la lumiere 

 qu'ils repandent," shows his power of accurate observa- 

 tion. He says that this property is not confined to the 

 skin or outer membrane of the Pholas, but that every 

 part of the body is imbued with it, and when the Pholas 

 is cut into pieces, each portion is luminous. Much of 

 the water that drops from them sparkles brilliantly. 

 The phenomenon is visible only when the Pholas is in a 

 moist state. He dried several specimens, and after four or 

 five days moistened some with common or fresh water, 

 and others with water in which sea-salt had been dis- 

 solved. In every case the phosphoric light reappeared, 

 but with less intensity than at first. When the Pholas 

 was put into brandy, the luminosity almost instantly 

 disappeared. No light is emitted by them in a dead or 



