Genus: Flask-shaped; elongate, flattened; anterior region neck-like; cilia only on right side; without trichocyst-borders; cytostome with trichocysts; two macronuclei (Kudo, 1966). Species: Long, thin and contractile; cell body is 200 μm long with a very long and thin neck region and pointed tail; laterally compressed; two macronuclei; a large contractile vacuole with small satellites (Carey, 1992). 500 μm long (Kahl, 1931).