Family: Anterior preoral kinetal arcs of all, body tapers at forward end.
Genus: Cell body ovoid, with pre-oral suture skewed left to a point; ventrally flattened, dorsally convex (How to know the protozoa, 1979). With distinct postoral ? beak or unciliated field in ventral body cilia; preoral kinety complete (Illustrated Guide, 1985). Dorsal surface lacks bristles (cf. with bristles Trithigmostoma) ; central zone devoid of cilia (Carey, 1992).
Species: Nineteen to twenty ventral ciliary rows; oral basket with about twelve rods (nematodesmata) and with three preoral membranes; macronucleus oval, a characteristic concentric structure; micronuleus small; body 100-300 μm long (Kudo, 1966). 130-150 μm long (How to know the protozoa, 1979). 45 μm long, numerous contractile vacuoles (Carey, 1992).