(Claparède and Lachmann, 1859)
Body pyriform, pre-equatorial furrow separating conical anterior portion from globular trunk; colour blue-green. Cytostome apical, surrounded by up to 12 retractile, forked processes. 1 to 2 (uncertain) spherical macronuclear nodules. Possibly 2 contractile vacuoles pre-equatorial in conical portion; posterior position very likely mistaken. Crescent-shaped vacuole of unknown function often in posterior end. Without extrusomes (?). 26-49 short, bipartite, longitudinal ciliary rows in area of pre-equatorial furrow; anterior portions form 3 pre-equatorial ciliary belts composed of anteriorly, laterally and posteriorly directed bundles of 14-20 µm long and stiff cilia ("cirri"), bundles only distally bifurcate, with 2-3 barbs; posterior portions form equatorial belt difficult to recognize because cilia closely adjoin pellicle. Dorsal brush absent (?). Moves in very rapid backward jumps, rests with pre-equatorial cilia rigidly spread. Often attaches to substrate with oral processes. Size in vivo 15-35 x 10-25 µm.
Ref.: Kahl (1930), Borror (1972a), Tamar (1992), Foissner et al. (1995).