No picture so far.
Cells have one main flagellum, many yellow-brown chloroplasts and a regular, usually hexagonal silica skeleton with spines. Naked stage in life cycle has one flagellum emerging from an apical depression and many yellow-brown chloroplasts. A naked ameboid stage lacking flagella may also be present
Dimensions of skeletons are 19-34 µm, not including spines. Naked flagellated stage measure 10-20 µm, flagellum 20-30 µm. A second, usually not visible and very short flagellum is present
Throndsen, J., Hasle, G.R. and Tangen, K., 2007. Phytoplankton of Norwegian coastal waters. Almater Forlag AS. 341 pp