Description: The cells are a little wider than long and octagonal in coarse shape. The central cut is deep and extends strongly outwards. The cell halves are oblong hexagonal with straight or weakly concave sides, the vertices are broadly truncated. At each lateral and apical angle a pair of long pricks originate. Above the center is a flat, often slightly brown colored swelling of the cell wall occupies with small warts.

Dimension: Length 45–55 µm, width 35–45 µm (without pricks).

Occurrence: In littoral zones of mountain lakes in Central Europe, rather rare.

Left: Original graphic by Prof. Lenzenweger.
Right: Completed binary fission. Photomicrograph by Prof. Lenzenweger. For microphotography, the microscope illumination was adjusted in such a way that as many features as possible that are important for species identification are prominently displayed.

Copyright by Prof. Rupert Lenzenweger, Ried im Innkreis, Austria.