Size in vivo about 350 × 65 µm; contractile by about 30% of body length. Asymmetrically lageniform with slightly curved anterior region and bluntly pointed posterior end; dorsoventrally flattened up to 2:1. 2 broadly ellipsoid, widely distant macronuclear nodules each with several globular to broadly ellipsoidal micronuclei. 2 types of extrusomes attached to oral bulge: type I rod-shaped and slightly curved, ~ 50 × 0.5 µm in vivo; type II rod-shaped to indistinctly acicular, ~ 5 × 0.4 µm in vivo. Usually green by symbiotic algae. About 40 ciliary rows; dorsal brush isostichad. Lepidosomes and slime produce a 5–7 µm thick mucilaginous layer easily recognizable in vivo. Type I lepidosomes discoid, in the SEM 1.6 × 0.7 × 0.5 µm and with 5 large polygons in superstructure on average; type IV ampulliform, 2.4 × 1.1 × 1.1 µm in size and with 8 polygons in superstructure; type IX mushroom-shaped, 2.5 × 1.9 × 2.4 µm in sized and with 8 polygons in superstructure.
