Cohn, 1866
Body ellipsoidal, highly flexible, slightly contractile. Two macronuclei, 2-3 micronuclei. Contractile vacuole near mid-body on left. Frontoventral cirri conspicuously shifted backwards, some behind level of cytostome. Three frontal, 3 frontoventral, 1 buccal, 3 postoral ventral, 2 pretransverse and 4-6 transverse cirri. Right marginal cirral row in posterior half of cell, composed of 3-9 cirri, not confluent with left marginal cirral row. Dorsal kineties 5-6 in number, with about 10 µm long cilia and 3 fine caudal cirri. Adoral zone of membranelles extending over about 20% of body length, composed of 13-18 membranelles of which first 5 appear spine-like, stiff. Movement jumping, rests in between. Size 50-100 x 30-40 µm. The species was recently transferred to Oxytricha (Song et al., 1991), which is not followed here since its morphogenesis, an essential feature for a generic classification in oxytrichids (Berger and Foissner, 1997), is not known and its dorsal ciliary pattern is rather peculiar.
Ref.: Kahl (1932), Dragesco (1963), Song et al. (1991).