74 MACTRADiE. 



mis, which is usually worn from the disk ; beaks large and protu- 

 berant, inclined a little forwards ; behind them is a broad, lance- 

 olate space, bounded by sharp ridges passing from the beaks to 

 the upper part of the basal angle, in which the epidermis is foli- 

 aceous, or very loosely wrinkled ; a much more faintly developed 

 areola may also be observed before the beaks. Hinge very strong, 

 spoon-shaped cavity very large and broad, the V tooth very deli- 

 cate, and adhering by a very small base, so that it is usually broken 

 off in the cartilage ; lateral teeth long and thin, striated on their 

 receiving surfaces. Muscular and pallial impressions very decided, 

 the posterior sinus of the latter quite shallow. Length, four and 

 one half inches ; height, three inches ; breadth, one and four fifths 

 inches. 



It is found about sandy beaches on all our coast, and its inhabi- 

 tant is much esteemed by some as an article of food; but it is a})t 

 to induce severe pain. At low water it is dug out of the sand with 

 shovels. At higher tides, when the shell is open, the fishermen 

 wade into the water, thrusting a pointed stick into the sand before 

 them, as they walk along. If the stick hai)})ens to pass between 

 the valves, they are closed upon it by the animal, and the shell is 

 thus drawn up. 



This is sufficiently characterized at maturity l)y its great magni- 

 tude, which entitles it to the name of giant clam. On the coast of 

 Long Island it is called beach clam and dipper clam. About Cajie 

 Cod it is called hen (an Indian name) clam or poqvaii, in distinc- 

 tion from the common clam which they called siki. The term />o- 

 quaii^ by corruption and plural termination gnaliaag-, is now aj)plicd 

 to the round clam {Vcmis mercenaria), while the latter term has 

 become obsolete. The Indians used them as hoes to hill corn with. 

 " In some places of the country there be clams as l)ig as a jienny 

 white loaf" (Wood's Neiv England Prospect). No other species 

 of the genus approaches it in size except the next, from which it 

 may be distinguished at all stages by its striated lateral teeth. The 

 largest specimen I have seen measures six and one fourth inches 

 in length, four inches in height, and two and one half inches in 

 breadth. It preserves its general features through all ages, ex- 

 cept that, when young, it is more nearly equipartitc, and, after it 

 has attained its full dimensions, it acquires great weight and thick- 

 ness. Some S})eciniens obtained in Provincetown Harbor, where 

 there are no rocks and little surf, are very light, thin, and white. 



A specimen from the cabinet of Colonel Totten, which he found 



