Genus: Body long, flask-shaped; apex a bulb with several short oblique kineties; contractile (Illustrated Guide, 1985). Spindle- or flask-shaped; with a long contractile proboscis; cytostome round; ciliary rows meridional or spiral to right (Kudo, 1966).
Species: Flask-shaped, 100 μm long; common species (Carey, 1992).