Marine bivalve (Panopea generosa) that inhabits the intertidal zone of the Pacific coast from southern Alaska to Baja California. It is the largest known burrowing bivalve, with a shell about 7–9 in. (18–23 cm) long and siphons that extend up to about 4 ft (1.3 m). It may weigh as much as 8 lbs (3.6 kg). Though highly prized for food, it lives in deep burrows and is difficult to dig out (the name probably derives from an Indian phrase meaning dig deep). Similar species are found in other parts of the world.