Genus: Cytostome at or ahead of equator (Illustrated Guide, 1985; cytostome behind equator -->> Uropedalium, Urocyclon, Homalogastra). Anterior region not ciliated; cytostome on the ventral side close to left border in the anterior half; contractile vacuole terminal (Kudo, 1966). Ovoid, pyriform or elongate; cytostome small just above the equator; caudal cilium; somatic ciliation bipolar; a macronucleus anterior; a contractile vacuole posterior (Carey, 1992). Species: 30-50 μm long; like pluricaudatum (see below), but has only one caudal cilium (How to know the protozoa, 1979). Macronucleus spherical; a single contractile vacuole posterior (Carey, 1992).

Similar Genus ->> Cyclidium; Pleuronema

50 μm 100 μm 150 μm; x 400

U. pluricaudatum Norland (or Noland): 25 μm long; body ovoid, with flattened anterior cap; spiral peristome; small undulatory membrane at base of peristome; about 8 caudal cilia; contractile vacuole at rear (How to know the protozoa, 1979).
U. marinum Dujardin, 1841: 30-50 μm long; like pluricaudatum, but has only one caudal cilium (How to know the protozoa, 1979). Macronucleus spherical; a single contractile vacuole posterior (Carey, 1992).