(Spengler, 1793)
Description:
A large thick shell shaped like Mya truncata but with a broad furrow in the middle of each valve. One very small tooth in the right valve and two teeth in the left (P. arctica-drawing).
Size:
Up to 50 x 75 mm. Some shells may reach the length of 125 mm.
Colour:
The shell is covered by a yellow-brown periostracum.
Animal:
The siphons are protected by a thick leathery sheath, and the lower tube is larger than the upper one.
Habitat:
Deeply buried in muddy or sandy ground from intertidal zone down to 300 m.
Distribution:
A very rare, circumpolar species. In Europe from the Lofoten Islands, Iceland south to the British Isles. Reported also from the Mediterranean. (Distr. P. arctica).