As Cuspidaria alveata:
Shell much inflated, nearly equilateral, umbo prominent, dorsal margin rather straight, anterior perpendicularly truncate, ventral rounded, posterior scarcely sinuate, rostrum hardly apparent. Colour cream. Sculpture, medially there are faint radiating impressed lines which vanish on the anterior quarter, but posteriorly gradually pass into deep and wide furrows. These furrows notch the margin and are parted by sharp elevated ribs of which about ten are stronger than the rest, the broadest furrows contain each a small interstitial riblet. Except the smooth umbo the whole surface is overrun by fine close concentric threads which bead the crests of the ribs. Length, 9,5 ; height, 8 ; depth of single valve 3 mm.

Tasman Sea