Stein, 1859
Outline elongate elliptical; 10-12 longitudinal dorsal ribs. Oral cavity large; lip on right border prominent, with characteristic protrusion in anterior portion. Macronucleus C- to slightly 3-shaped, 1 micronucleus anteriorly near macronucleus. One contractile vacuole. Ten frontoventral, 5 transverse, 2 left marginal and 2 caudal cirri. Dorsal kineties 11-13 in number, with 36-45 cilia in central rows. Adoral zone extends over about 2/3 of body length, composed of 52-70 membranelles. Dorsal silverline system of double-eurystomus type. Length 120-260 µm.
Ref.: Kahl (1932), Tuffrau (1960), Curds (1975), Dragesco and Dragesco-Kernéis (1986).