Ehrenberg, 1838
Body ovoid to elongate ovoid, generally small to very small, with sparse ciliation and distinctive caudal cilium. Cytostome variable in position, oral ciliature less prominent than in Pleuronematidae. Macronucleus and large micronucleus often located in anterior 1/3 of body. Widely distributed, freshwater, brackish, marine, interstitial, edaphic, coprozoic.
Planctonic species recorded:
Cyclidium glaucoma