quahog Mercenaria mercenaria, one of the most popular clams in N. America, is known also as littleneck, because the ‘neck’ on which its syphons protrude is much shorter than that of its principal rival, the soft-shelled clam; and as hard(-shelled) clam, because its shell is much stronger and thicker than that of the other.
The name quahog (pronounced co-hog), or quahaug, is of American Indian derivation. The species is a native of N. America, with a range extending from Canada down to Florida, but has established for itself (via the kitchens of ocean liners) English colonies in Southampton Water and Portsmouth harbour; and has also been introduced to the south of Ireland and the basin of the River Seudre in France. The French, in deference to its American origin, call it ‘clam’.