Genus (Ehrenberg, 1830): Spheroidal; cytoplasm vacuolated, especially ectoplasm; nucleus central;
one to many contractile vacuoles; axopodia straight, axial filaments terminate at surface of the
nucleus (Kudo, 1966).
Species: Ectoplasm vacuolated; a large central nucleus; diameter average 40-50 μm (Kudo, 1966).
Images of collecting locality:
No.1, Kannon-numa Forest Park (pond), Shimogo town, Fukushima Pref., Japan, November 15, 2008, by Y. Tsukii