Raphe straight, without distinct terminal raphe fissures
Striae unseriate, slightly radiate throughout both valves
One or two striae in the center of the raphe valve more broad than the other striae
Valves are linear to linear-elliptical or linear-lanceolate with rounded ends. The terminal raphe fissures are not distinct. The striae are uniseriate, with 4-5 areolae per stria, and slightly radiate throughout both valves.