Valves are strongly dorsi-ventral. The dorsal margin is broadly arched, while the ventral margin is distinctly gibbous. The number of dorsal, central striae is important in distinguishing this species from similar species, as well as the density of areolae in a central, dorsal striae. Ventrally, central striae number 9 in 10 μm, and distal striae number 5 in 5 μm. The density of areolae within a central, dorsal stria is 9 in 5 μm.