Body ovoid, right side straight, left convex, anteriorly slightly narrowed but both ends broadly rounded; laterally more or less flattened. Oral area extending from anterior pole to posterior 1/6 of body. Contractile vacuole dorsal in posterior 1/5 of body. Resting extrusomes rod-shaped according to Kahl's (1931) drawing, distinct in life. Somatic kineties densely ciliated, cilia on posterior pole not elongated. Movement rapidly to and fro, rests with cilia spread when feeding. Length 70-120 µm.
Ref.: Kahl (1931).