- Rotational symmetry of cell face outline 180 degrees, with the ends being opposite reflections of each other
In this section
Roughly boat-shaped in valve view, although long narrow ends may be present in some species; valves identical, each possessing a raphe (genus is biraphid). Raphe lies beneath fibulae on one edge of the valve. Raphes are on opposite sides on each valve (unlike Hantzschia, in which they are on the same side; however, this may be difficult to discern).