Genus: Oral cavity deep, opens ventrally away from apex; more internal tubular part precedes cytostome; the tubular part of oral vacity extends to left (Illustrated Guide, 1985). Body laterally compressed (Carey, 1992). Species: Ovoid, dorso-ventrally flatted; cell body uniformly covered with long cilia; a raised lip on the anterior edge of cytostome; 80-180 μm long (Kojima et al., 1995). Cell body ovoid, rounded at both ends, oral region short and slit-like, wide, ccurved transversely striated ribbon extends from posterior end, a single macronuleus ovoid, a single micronucleus present (Carey, 1992).

50 μm 100 μm 150 μm; x 400

Plagipyla nasuta Stein, 1860: Ovoid, dorso-ventrally flatted; cell body uniformly covered with long cilia; a raised lip on the anterior edge of cytostome; 80-180 μm long (Kojima et al., 1995).

Plagipyla nasuta (Stein, 1860) Agamaliev, 1978: Cell body ovoid, rounded at both ends, oral region short and slit-like, wide, ccurved transversely striated ribbon extends from posterior end, a single macronuleus ovoid, a single micronucleus present (Carey, 1992).

Plagipyla binuleata Agamaliev, 1978: cell body ovoid and flattened, 80-100 μm long, enlarged cilia surround the transverse slit-like oral region, vestibule short and conical, 60-70 kineties, transversely striated ribbon wide and curved, two macronuclei and an intercalated mironucleus present, a single contractile vacuole posterior (Carey, 1992).

Plagipyla frontata Kahl, 1931: Ellipsoidal; oral cleft anteriorly; posterior rounded; 80-120 μm long; vestibule large with distinctive ciliation and a raised lip on the posterior edge; a large macronucleus & a micronucleus; a single contractile vacuole in the rear; a short field of longer caudal cilia (Carey, 1992).