THE SHELL-FTSH Of THE COAST. 35 



by means of its active and greatly elongated foot. 

 It seems never to construct a permanent burrow, 

 thus differing from the ' long-clam' or ' sand- 

 clam,' to be noticed hereafter. The shells, which, 

 when full grown, measure as much as six inches 

 in length and four inches iu height, were formerly 

 used by the Indians as hoes in the hilling of corn. 

 Two smaller species, Mactra ovalis and M. lateralis, 

 are abundant at some tides. 



Thci round clam or quahog, which is the clam of 

 the N"ew York and Philadelphia markets, inhabits 

 the muddy bottoms of bays more particularly from 



QuAHOQ { Venus mercenaria). 



low-water mark to about 30 fathoms. Its habitat 

 extends along the entire American coast from Cape 

 Cod to Florida, but north of Cape Cod it is of 

 rare occurrence. The quahog is a large and pow- 

 erful shell, whose outer surface frequently shows 

 signs of considerable erosion. From the interior 



