Family: Oral area subapical, ovoid, flattened, anlong ventral margin of laterally compressed body; both side ciliated (Illustrated Guide, 1985).
Genus: Flask-shaped; elongate, flattened; anterior region neck-like; cilia only on right side; without trichocyst-borders; cytostome with trichocysts; two macronuclei (Kudo, 1966).

Litonotus sp., cell body μm long, μm wide, x 400, x 640, Japan, 1998 by Y. Tsukii