Nuclearia simplex Cienkowski, 1865
Diagnosis: Amoeboid organism with non-granular, non-anastomosing filopodia, body commonly spherical but also flattened, from round to elongated and fusiform; nucleus spherical with smooth nucleolus.
Dimensions: c. 30 µm.
Remarks: Cienkowski (1865) observed encystment followed by the liberation of young amoebae. Pernin (1976) described the amoeboid form of N. simplex from observations of specimens under a cover slip.