(Claparède and Lachmann, 1858)
Body broadly fusiform, narrowed posteriorly, right margin distinctly convex, vaulted dorsally. Macronucleus possibly fragmented. Colour yellow-brown to reddish, sometimes colourless. Two left marginal, 1 right marginal, 2 midventral cirral rows. Adoral zone of membranelles along about 1/3 of body length, extending far onto right side. Size 110-150 x 45-55 µm.
Ref.: Hamburger and Buddenbrock (1911), Kahl (1932).