| Diagnosis |
Shell solid, medium sized, higher than long and rounded-ovate in outline. Both valves convex and subequal, the right (lower) valve a little flatter than the left (upper) valve. Ears markedly unequal in size, the anterior ones more than twice the length of the posterior ones. Ventral side of right anterior ear with a deep byssal notch and a ctenolium. Main sculpture of each valve of 20 to 26 rounded often with fine secondary radial threads, and with microscopic lines, obliquely diverging on anterior and posterior sides of valves. Ears strongly ribbed, the dorsalmost rib of right anterior ear somewhat protruding and adorned with erect spines. Interior shiny, with low, rounded radial ribs corresponding to the outer sculpture. Colour: outside of shell variable, dull purple, brown or orange, frequently variegated with paler blotches. Interior similarly coloured, suffused with white on hinge and umbonal cavity. |