Frustules biraphid, linear to elliptical in outline. A common species (C. solea (Bré) W. Smith) is constructed about the central portion of the valve, while C. cochlea is twisted about the apical axis. Apices round to apiculate. Valves symmetrical to the apical axis, symmetrical or asymmetrical to the transapical axis. Raphe positioned in a wing around the periphery of the valve. Valve surface with regular undulations. Striae distinct.

A small but common genus occurring in benthic communities of lakes and slow-flowing rivers.

Light Microscope Image(s)