Cavinula Mann and Stickle
Biraphid valves, symmetric to the apical and transapical axis. One or two chloroplasts, H-shaped in girdle view. Valves linear-lanceolate to nearly elliptical. Uniseriate striae, composed of round to elongate puncta. Central sternum thickened internally. External proximal raphe expanded, internal proximal raphe straight. A freshwater genus reported from oligotrophic lakes or moist subaerial habitats.