(Linné, 1758)
Description (shell):
Shell thin and brittle, elongate-oval; umbones subterminal, above a curved anterior margin. Hinge line at a steep angle to umbones, ventral margin slightly concave; umbonal ridges very prominent, rounded, almost parallel with ventral margin. Periostracum produced into dense fringes of flattened, serrated spines which are present in even the largest specimens, though often abraded at anterior end, and may trap quantities of silt and detritus. Sculpture of fine concentric lines; growth stages clear where not obscured by periostracum (M. barbaratus-drawing).
Size:
Up to 60 mm long.
Colour:
Shell yellowish white to light yellow or reddish brown. Periostracum glossy, yellow, reddish brown, or light mahogany, lighter along umbonal ridges. Inner surface of shell pale bluish white, with tinges of red or light purple.
Habitat:
Distributed from lower shore to about 100 m, on coarse grounds.
Distribution:
Ranging south to the Mediterranean and north-west Africa (Distr. M. barbatus).