« Shell sub-cordate, smooth, white, covered with an olivaceous epidermis ; umbo very small ; beaks slightly inflected, and placed near to one end. Inside smooth, white, and somewhat nacred ; margin thin and entire ; hinge pectinated with fifteen elevated teeth placed within the margin, six on one side, and nine on the other, divided by a small concave plate that projects inwards. » – G. Montagu: Supplement to Testacea Britannica with Additional Plates, London 1808, p.56-57.