THE NATURALIST'S GUIDE. 107 



MYTILID^E, Salt-water Mussels, may be found on 

 banks left exposed by the tide, or adhering to posts, 

 etc., which stand in the water, or embedded in salt 

 marshes. They may be scalded and cleaned ; but care 

 should be taken to preserve the byssus, that is, the 

 ligament by which the shell fastens itself to rocks, etc. 



PECTENID^E, Scallops. These are found on grassy 

 mud-flats that are not left exposed by the tide. They 

 may be scalded and cleaned. 



OSTREID^;, Oysters, are found on bars, at the mouths 

 of rivers, where the fresh and salt water mingles. 

 They may be scalded and cleaned. Some, however, 

 are found in salt water, clinging to other shells, stones, 

 etc. 



TEREBRATULID^E. Found usually in deep water, 

 off the coast. 



BULLID^:. These are fragile, univalve shells, found 

 on mud-flats, at low water. They should be boiled, 

 cleaned, and wrapped in cotton. 



DORIDID^E, TRITONIID^;, ^EOLIDID^E, ETC. These 

 are shell-less Mollusks, found adhering to seaweeds. 

 They are to be preserved in alcohol. They form fine 

 objects for the aquarium. 



CHITO:STD., Chitons. This interesting class of Mol- 

 lusks which are covered with armadillo-like bands, are 

 found clinging closely to the rocks between tide-marks. 

 The animal should be removed with a knife, and the 

 shells laid flat on a plain surface ; then, a board laid 

 over them, to keep them from curling when they dry. 



DESTTALID^E, Tooth-Shells, are dredged from great 

 depths. They are cleaned by boiling. 



PATELLID^E AISTD CALYPTR^ID^E, Cap-Shells, cling 

 to rocks, shells, etc. They must be taken unawares 

 from the surface to which they cling, or it will be 



