Genus Polychaos Schaeffer, 1926
Diagnosis: during active locomotion usually polypodial, palmate, with several tubular pseudopodia, more or less equal and with no one dominant, proceeding anteriorly and anterior-laterally from common posterior mass; posterior of cell often with a bundle of fused, remnant pseudopodia; pseudopodia sometimes flattened and broadening towards ends; monopodial in rapid locomotion with a bulbous uroid; no dorsal ridges; nucleus granular or with other arrangements of nucleolar material; crystals irregular or plate-like to bi-pyramidal, some as paired bodies or clusters.
Key to the species:
|1||Nucleus with a ring- or belt-shaped nucleolus||
|2||Nucleolar material in few narrow peripheral lobes, sometimes in a single curved band, twisting inside the nucleus.||P. fasciculatum|
|–||Nucleolar material forming a perforated sphere inside the nucleus.|
|3||Nucleus discoid, spheroid or ovoid||P. dubium|
|–||Nucleus shallowly to deeply cup-shaped||P. nitidubium|