Length 32 mm. LWS. Isle of Lewis, Scotland. April 2018. Leg. D.W. McKay & S.Taylor
The shell colour is various combinations of white, cream, shades of brown, red and ochre arranged in blotches or intricate zig-zag lines. In this image the green hue on the valves may be epiphytic algae. The posterior beaks on the keeled jugum of valves ii to vii are well developed on this specimen; they are often eroded.
The head valve (i) is almost semicircular, with a shallow V posterior edge when viewed in situ on a living specimen.
The perinotum (dorsal cuticle of girdle) is yellowish with, usually, a brown or purplish band at each end of valves ii to vii, and several bands associated with valves i and viii. Very frequently, the dorsal girdle is partly or completely overcast with a distinctive verdigris-green. On dead specimens the bands usually become obscure, and preserved ones usually have a plain, dull brown girdle.

marinvert.senckenberg.science/image-browse/