34 THE SHELL-FISH OF THE COAST. 



on the interior of the shell connects the adductor 

 impressions. This sinual inflection, or ' pallial sinus,' 

 IS one of the most important characters to be noted 

 in the shell, since it serves to indicate a prominent 

 feature in the structure of the animal. 



We recognize two hard-shell clams on our coast, 

 one having an obliquely oval shell, the quahog 

 ( Venus mercmaria), and the other, with a more nearly 



Shkf-clam (Maclra solidissima). 



triangular or equilateral shell, the Mactra (Mactra 

 solidissirna). The former is the edible species, al- 

 though by some the Mactra is not completely de- 

 nied a hearing. The latter, also known as the 

 ' sea-clam' or ' surf-clam,' inhabits the sandy coasts, 

 where it lies buried just beneath the surface; 

 but it may be occasionally seen skipping about 



