sea clam

from the GNU version of the Collaborative International Dictionary of English.

• (Zoöl.) Any one of the large bivalve mollusks found on the open seacoast, especially those of the family Mactridæ, as the common American species. (Mactra solidissima or Spisula solidissima); -- called also beach clam, and surf clam.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun The Atlantic surf clam.