Synonyms for Quahaug (same or very similar meaning)
WordNet sense 1 (Atlantic coast round clams with hard shells; large clams usually used for chowders or other clam dishes):
quahog, hard-shell clam, round clamWordNet sense 2 (an edible American clam; the heavy shells were used as money by some American Indians):
hard clam, Mercenaria mercenaria, Venus mercenariaFrom the ODE community, based on WordNetadd/edit