(Pennant, 1777)
Description (shell):
Shell elongate-oval, umbones distinctly anterior; hinge line sloping anteriorly, almost straight posteriorly, posterior margin smoothly rounded. Concentric sculpture of numerous fine grooves, no radiating sculpture. Growth stages clear. Lunule elongate, shallow, darkly tinted; escutcheon elongate, narrow, ill-defined. Three cardinal teeth in each valve, centre one of left valve, and centre and posterior of right, bifid. Adductor scars and pallial line distinct; pallial sinus U-shaped, extending to a point below the posterior edge of ligament (P. rhomboides-drawing).
Size:
Up to 60 mm long.
Colour:
Cream, fawn, or light reddish brown, typically with streaks, blotches, or irregular rays of chestnut, light purple, or pinkish brown. Inner surfaces glossy white, with a pinkish tinge beneath hinge line.
Animal:
The margin of the mantle is partly toothed and partly waved and scalloped. The siphons are separate for only a fourth of their length, and are pale yellow, tinged with brown and purple, and with fringed openings.
Habitat:
In coarse sands, gravel, and shell-gravel, from the lower shore, perhaps to the edge of the continental shelf.
Distribution:
Distributed from Norway to the Mediterranean and north-west Africa (Distr. P. rhomboides).