Entomoneis punctulata

Frustules are very lightly silicified and come to rest primarily in girdle view, a view which is dominated by two highly arched bilobate keels, one on each valve. The keel lobes are broadly rounded and the keels are only slightly torsioned so that both lobes are more or less in focus at the same time. A row of dots, that may be determined to be fibulae, follow the contour of each lobe a short distance from the keel margin. The short, curved junction line between valve face and keel is restricted to a terminal portion of each lobe of the keel. The cingulum is composed of five or six open bands. Striae are very faint and continuous from the valve face onto the keel without differentiation. The fine structure of the striae cannot be resolved in LM.