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, 250 μm long; frange reduced; cytopharyngeal basket long; a single contractile vacuole (Carey, 1992).

Similar species --> Paranassula

50 μm 100 μm 150 μm; x 400

31 μm 63 μm 94 μm; x 640

Nassula aurea Ehrenberg 1833, cell body ellipsoidal, 275 μm long, 180 μm wide, cyrtos 24 μm in diam., length unknown, trichocysts absent, a contractile vacuole with many peripheral small vacuoles, x 100, x 200, x 400, x 640, Torinome Kasen park, Nasu-shiobara city (formerly Kuroiso city), Tochigi Pref., Japan, January 1999 by Y. Tsukii
100 μm 200 μm 300 μm; x 200 : 50 μm 100 μm 150 μm; x 400

100 μm 200 μm 300 μm; x 200 : 50 μm 100 μm 150 μm; x 400

Nassula ornata Ehrenberg, 1833: 250 μm long, 180 μm wide (Kahl, 1931). Ovoid, 250 μm long; frange presents; a single contractile vacuole lie in the mid-body region; macronucleus with at least three micronuclei; many trichocysts present (Carey, 1992).

* Nassula aurea Ehrenberg, 1833: 250 μm long; L/W=2 (Kahl, 1931). Ovoid or elliptical, 250 μm long; reduced frange presents; long cytopharyngeal apparatus "cyrtos" presents; macronucleus with 2 to 4 micronuclei; a single contractile vacuole; trichocysts absent (Carey, 1992).

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).