« Venus with a sub-oval, sub-triangular, yellowish-white shell, wrought with numerous, fine, concentric, parallel, equidistant, elevated, and somewhat reflected ridges, about thirty six in number. These ridges at the anterior side, on the margin of the cartilage slope, on both valves, become confluent in pairs, and form short, obtuse spines, reflecting backwards ; this double row of spines forms a deep cavity for the cartilage. Umbo small, nearly central, and turned a little to one side, beneath which, is a strong, lanceolate, cordiform depression. Inside smooth, white ; hinge furnished with a single primary tooth, and a small cavity on each side in one valve, which locks in between, and reciprocally receives two in the other valve ; the former has also a remote, lateral Lamina on each side, which the latter is destitute of, or very obsolete. The margins are plain. » – G. Montagu: Testacea Britannica, London 1803.