Description of Amoeba proteus: Length of this species in locomotion about 220-760 microns (mean 425 microns). Nucleus discoid, often concave, 22-62 microns (mean 40 microns), nucleus with thickened wall. The majority of the cells are usually polypodial under favourable conditions, with lobose pseudopodia, with a small minority of cells being monopodial. With posterior rumpled uroid. Has world-wide distribution.