Genus Nuclearia Cienkowski, 1865
Diagnosis: Small to medium-sized amoebae, either naked or with mucus sheath, either flattened with pseudopodia extending predominantly from one margin and/or adopting a rounded body form with radiating pseudopodia, in which form they may be confused with heliozoa but can be distinguished by the absence of extrusomes. May form organic walled (mucus-sheath) cysts. Typically without color (cf. vampyrellids with which they have previously been classified). Genus revised by Patterson (1984).