Cells elliptical, linear-elliptic, lanceolate. Frustules heterovalvar and slightly curved, raphe valve slightly concave, rapheless valve slightly convex. Valves isopolar and bilaterally symmetrical.
Girdle and mantle narrow, girdle bands without perforations.
Striae uniseriate, biseriate or triseriate; areolae occluded by hymenes.
Raphe straight with small or slightly dilated ends. Distal raphe ends do not extend onto mantle.