196 



CONCHIFERA. 



FIG. 156. LIMA. 



The Scallops (Pecteti) sometimes attach themselves to rocks, and some- 

 times cover extensive banks. These bivalves are said to be able to see, and 

 certain bright spots upon the margin of their mantle are believed to be eyes; 

 indeed, one species has been named, after Juno's watchman, the Argus. 

 Whether these brilliant pearl-like specks, so strangely situated, are really in- 

 struments of vision is, however, open to doubt. 



FIG. 197. GREAT SCALLOP. 



The Pearl-Shells (Amenta). To this family belongs the celebrated 

 Pearl-Oyster. Their shells are imported in immense quantities, forming the 



