The valve of this taxon is linear and slightly swollen in the middle and at the ends which are rounded. The axial ends are one third of the width of the valve and the central area is large and elliptical. The raphe is complex, there are terminal fissures which are distinct and shaped like a question mark. Ther terminal nodules are large. The striae are radiate in the center and convergent at the ends and crossed by a broad band. (Patrick and Reimer 1966).