I.A.N.Lucas (1968: 437, figs 1–5)
Cells ovoid, 3.2–3.8 µm diameter, biflagellate. Flagella unequal, c. 15 µm long and c. 4 µm long. Cell body covered with 3 types of scales: plate scales, crown scales and pyramid scales (isolated scales observed). Plate scales oval, 0.75–0.9 µm long, 0.54–0.62 µm wide, built of radial rods supporting an inner oval ring. Crown scales similar but bearing an upright crown-like structure supported on 3 or 4 struts to 0.2 µm high from an inner oval ring. Pyramid scales 0.73 µm basal diameter, with a central pyramid-like structure comprising 3 or 4 struts; overall length of scale 1.2–1.62 µm.
Southern Ocean, south of Australia; Plymouth Sound, Great Britain (Lucas, 1968).