Genus: Body long to ovoid; apex fan-shaped; txicysts evenly distributed along edge of apex (Illustrated Guide, 1985). Body elongate, circular in cross section; antrerior obliquely truncated, surmounted by an unciliated apical ridge, which is lined with trichocysts; cytostome slit-like (Carey, 1992). Very many species (Corliss, 1979). Species: Cell body 120, 600 μm long (Kahl, 1930).

50 μm 100 μm 150 μm; x 400 : 31 μm 63 μm 94 μm; x 640