Rhizamoeba coerulea (Schaeffer, 1926) Siemensma, 1987
Diagnose: Medium-sized to large amoeba, which can spread very flat with very fine subpseudopodia, sticked to the substrate; polypodial form usually covered with detritus; monopodial form bat-shaped; numerous, up to 32 small nuclei; cytoplasm clear, with many very small granules and some elliptical crystals; several contractile vacuoles; hyaloplasm at the anterior end with eruptive bulges; hyaloplasm may run back along the sides.
Dimensions: my measurements 150-260 µm, nuclei 4.8-24.0 µm (Penard 5-7 µm); Schaeffer (1926) 150 µm.
Ecology: Fresh water. I found this species in a stream near Epe (1980) and in a pond at Groeneveld (2012), both in the Netherlands. All amoebae were collected from floating detritus.
Remarks: It is possible that this species is identical with R. clavarioides.