Cells and setae have many small chloroplasts. The terminal setae (end setae) are different and shorter from the others in direction (form usually a V). Chains are straight and hexagonal windows are formed by the setae crossing outside of the chain edge. All valves have a central labiate process with a tube shaped and often long external part.
Apical axis measure 10-40 um.
Throndsen, J., Hasle, G.R. and Tangen, K., 2007. Phytoplankton of Norwegian coastal waters. Almater Forlag AS. 341 pp.