Diagnosis: All species with a spherical, colorless, hyaline smooth test, without any xenosomes; pseudostome with a small neck. Nucleus spherical but often distorted. Cells aggregate to capture food particles.
Dimensions: diameter 19-21 µm, length including neck 25 µm. Nucleus 7-8 µm (n=7)
Ecology: small forest pond, bordered with Sphagnum (Hollandse Rading, the Netherlands).
Remarks: I observed a group of three aggregated cells which divided within some hours, resulting in a "colony" of six cells.