Diagnosis: Locomotive form monopodial with a prominent anterior hyaline zone. Locomotion steady, non-eruptive. Cytoplasm without prominent cytoplasmic crystals but frequently with many small crystals. Often with a contractile vacuole. Forms round, or slightly oval, smooth bilaminar cysts.
Ultrastructure: Glycocalyx thin, some with cup-like surface structures, around 12.5 µm in diameter. Mitochondria, of those species examined, sometimes elongate.
Habitat: widely distributed in freshwater, also marine species.
Remarks: Distinguish from other limax amoebae of the class Heterolobosea, and families Leptomyxidae and Amoebidae by comparing features of the groupings. Many inadequately described species in this genus including type species.