Cladotricha variabilis Ruinen 1938

Hypotrich ciliate, one row each of right and left marginal cirri. The frontal cirri are in 2 groups, one longitudinal-oblique group of 4-7 cirri that lies parallel to the right marginal cirri of 5-8 cirri. The post-buccal cirri are in an oblique row of 5-8 cirri, with an additional row of 1-4 cirri to the left of the anterior end of that row (sometimes absent). Each frontal cirrus contains 4-6 cilla. The dorsal ciliature consists of a short inconspicuous oblique row of ~3 cilia adjacent and dorsal to the anterior terminus of the right marginal cirri; an oblique helical 'mid-dorsal' series of about 10-12 cilia, the last 2 of which are differentiated into caudal cirri with ~2 cilia apiece and 1-2 additional cilia, and a terminal caudal cirrus immediately to the observer's left of the longer row. In living ciliates, the cortical cytoplasm is free of visible granulation. The caudal cirri are stiff and vibratile, and protrude nearly vertically. The buccal cavity is about 30 microns long, the posterior 1/4 is narrow and cylindrical. Most of the paroral apparatus is deep in this posterior section of the buccal cavity. The ciliate is supple, and usually contorted in the living state, with the right marginal row of cirri usually twisted about 180 degrees.