Genus: Small, 15-60 μm long; with a caudal cilium; on the right edge of peristome occurs a membrane which forms a pocket around cytostomal groove; contractile vacuole posterior (Kudo, 1966). Ovoid body with flattened anterior cap; long peristome with large, undulatory membrane, extended in feeding, one long caudal cilium (How to know the protozoa, 1979). No somatic cilia at the anterior apex; no cilia around the posterior where a single, long caudal cilium usually merges; buccal ciliature proportionally smaller in comparison to Pleuronema (Carey, 1992). Species:

Similar Genus ->> Uronema; Pleuronema

50 μm 100 μm 150 μm; x 400

Cyclidium candens Kahl, 1928: Ovoid but elongate, 35-40 μm long; with longitudinal ridges in the pellicle; buccal apparatus 1/3 body length; a single very long caudal cilium (Carey, 1992).

Cyclidium citrullus (Cohn, 1866) Kahl, 1931: Ovoid, both anterior and posterior form small bump; 30 μm long; buccal ciliature 1/2 body length; a single caudal cilium; a spherical macronucleus; a contractile vacuole (Carey, 1992).