Genus (laparède and Lachmann, 1858): Ovoid or cylindrical; apical cytopharynx; posterior bald; caudal cilia present; contractile vacuole posterior (Carey, 1992). Species:

50 μm 100 μm 150 μm; x 400

U. farcta (Stokes, 1886) Kahl, 1930: Small; 20 μm long; pyriform or pyramidal in shape; posterior without ciliation except for a singlecaudal cilium; cytostome small; macronucleus spherical, centrally placed (Carey, 1992). --> U. farcta ?? (Kudo, 1966).