Genus: Cytostome just behind equator, in 3rd quarter of body (Illustrated Guide, 1985). Ovoid or crescent, usually both anterior and posterior pointed; somewhat flattened with a ridged, ribbed armour; somatic cilature reduced; cytostome in a depression on the left side at the centre of the body; fibrous trichocysts (Carey, 1992). Species: Cell body 35 μm long (Kahl, 1930).