Mussel and Cockle. 95 
are then more slender than those produced at 
leisure, and, of a consequence, weaker. On some 
parts of the Mediterranean coast, as in Sicily, 
gloves and other articles have been manufactured 
from the threads of this mollusk. They resemble 
very fine silk in appearance. 
The foot of the Cockle, of which we here give 
a fioure, is commonly employed in scooping out the 
mud or sand, beneath which it 
conceals itself; this useful limb 
assumes the form of a shovel, 
hook, or any other instrument 

necessary for the purpose; it 
appears to be a mass of muscular fibres, and to 
possess great power. As a boatman in shallow 
water sends his vessel along by pushing against 
the bottom with his boat-hook, precisely so does 
Mr. Cardium travel; he doubles up his foot into a 
club, and by an energetic use of it as a propeller, 
makes considerable headway along the surface of 
the soft sand beneath the waters. In this way, 
too, some members of the genus solen force their 
way through the sand ; while those called Tellina 
spring toa considerable distance, by first folding 
the foot into a small compass, and then suddenly 
expanding it, closing the shell at the same time with 
