Zlussel and Coclch, 05 



are tlien more slender tlian tliose produced at 

 leisure^ aud^ of a consequence^ weaker. On some 

 parts of tlie Mediterranean coast, as in. Sicily, 

 gloves and otlier articles have been manufactured 

 from tlie tlircads of this mollush. They resemble 

 very fine silk in appearance. 



The foot of the Cockle, of which we here give 

 a figure, 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 to a considerable distance, by first foldiug 

 the foot into a small compass, and then suddenly 

 expanding it, closing the shell at the same time witk 



