Family: Body ellipsoidal, uniformly ciliated; hypostomial frange short; prominent cytopharyngeal apparatus (Carey, 1992). Genus: Oral aperture small, oval (Carey, 1992). Species: Cell body ovoid or ellipsoidal, 150-210 μm long; anterior quarter narrower than the rest of the body with a shallow depression on its left margin onto which cytostome opens; macronucleus ovoid, deformable, a single micronucleus; trichocysts absent; a single terminal contractile vacuole ? (Carey, 1992).

Similar species --> Paranassula

50 μm 100 μm 150 μm; x 400

* Nassula terminalis Ozaki & Yagiu, 1941: Ovoid, flattened and flexible; 150-210 μm long; anterior quarter narrower than the rest of the body; cytopharyngeal opening very long; macronucleus ovoid; single micronucleus; single contractile vacuole terminal; trichocysts absent (Carey, 1992).

Nassula parva Kahl, 1928: Small, ovoid with large cytopharyngeal basket; 60 μm long; a spherical macronucleus; single contractile vacuole in mid-body region; details of range and suture not given (Carey, 1992).

Nassula rubens Perty, 1852: Small, ellipsoidal; 50-70 μm long; long cytopharyngeal basket; single contractile vacuole; single macronucleus; many trichocysts (Carey, 1992).

Nassula citrea Kahl, 1931: Ovoid or ellipsoidal, anterior not expanded; 70-90 μm long; frange equipped with long membranelles; cytopharyngeal appratus unremarkable; single contractile vacuole; single ovoid macronucelus (Carey, 1992).