THE SHELL-FISH OF THE COAST. 85 
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 in 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. 
The round clam or quahog, which is the clam of 
the New York and Philadelphia markets, inhabits 
the muddy bottoms of bays more particularly from 
‘QUAHOG ( 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 
