A number of valves from off North Cape, in 75 fathoms, differ from all other described New Zealand species in the characters of the left valves. These are thin, transparent (apart from a deposition of white callus over the upper third) and shining, the only sculpture consisting of sparse, irregular, microscopic radial scratches. The ears are subequally developed, well marked off from the disc, the valve being almost equilateral. Right valve very similar in texture, sculptured with more regular concentrics crossed by very fine, close but irregularly developed radials which are most obvious on the growth lines. Posterior ear sculptured with very fine growth lines, anterior ear indented by a strong byssal sinus, upper portion of ear with three radials. Length, 2,6 mm.; height, 2,4 mm.; inflation, 0,45 mm.