Family: Oral area subapical, ovoid, flattened, anlong ventral margin of laterally compressed body; both side ciliated (Illustrated Guide, 1985).
Genus: Flask-shaped; ciliation uniform and complete; slit-like cytostome not reaching the middle of body, without trichocyst-borders; two or more macronuclei (Kudo, 1966). Many contractile vacuoles along both dorsal and ventral edges (Carey, 1992).