XII. CLAMS, OYSTERS, AND MUSSELS 



MoLLTJSCA {continued) 

 Class I. — Pelecypoda (hatchet-footed) 



The clams, oysters, and mussels belong to this class. The 

 bodies.of all are soft and mclosed in a bivalve shell. 



Clams. —Perhaps the two species of clams best known 

 because most eaten are the long clam (Mya) and the round 

 clam (Venus). The round clam, also known as the "qua- 

 hog," "httle neck clam," etc., is characteristic of the 

 warmer waters. It is common on sandy shores and on 

 muddy flats, just beyond the low-water mark, from Cape 

 Cod to Texas. It burrows a short distance below the sur- 

 face, but is often found plowing at the surface with its shell 

 partly exposed. 



On the other hand, the long clam, or soft-shell clam, is an 

 inhabitant of cooler waters and extends north to the British 

 Provinces, although it overlaps and extends into the terri- 

 tory occupied by the round clam. The long clam is re- 

 markable for the length of its siphons. These constitute 

 the so-called "head," or "neck" and can be extended from 

 three to four inches beyond the valves of the shell (Fig. 60). 

 When quite young, the long clam begins a burrow in the 

 mud and keeps on enlarging and deepening it as it grows 

 older, until the clam may finally reach a point eight or ten 

 inches below the surface. While lying at the bottom of this 

 burrow, the long siphons are extended up to the surface of 



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