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Description of Pleuronema coronatumCiliate, 60-90 x 30-50 microns, outline elongate oval to elliptical, widest at or behind mid-body; anteriorly and posteriorly broadly rounded; ventral margin almost straight and dorsal side conspicuously convex. Dorso-ventraly about 3:2 f1attened. Pellicle rigid and slightly notched; extruomes about 4 microns long, closely arranged beneath pellicle. Cytoplasm colourless and hyaline, often containing several to many refractile globules which are mostly 3-5 microns across and located in the posterior half of the cell. Contractile vacuole small, located slightly dorsally in posterior 1/5-1/6 of the cell length (at about level of cytostome). Food vacuoles usually large, with indefinable contents (possibly bacteria). Macronucleus roundish, usually with many globular nucleoli. In some speciemens only one large, centrally located nucleolus to be observed. Single oval to spherical micronucleus closely adjacent to macronucleus. Somatic cilia about 10 microns long, about 10-15 caudal cilia about 3 times as long as somatic ones, stretching always in radial manner; cilia of buccal apparatus 20-40 microns length. Movement moderately fast, somewhat drifting and wobbly, and then motionless for short periods on detritus. About 40 somatic kinetics extending over entire length of cell, which are shortened anteriorly and form thus an inconspicuous suture, while others terminate at the apical end and compose one large bold apical plate. Caudally one cilia-free area to recognise posterior to buccal field. all kineties in anterior 2/3 of body composed of (mainly) paired basal bodies, monokinetids posterioly. Left of buccal field mostly 4-5 shortened kineties. Adoral membranelle short, anteriorly with two rows of basal bodies: membranelle 2 bipartite - one part posteriorly hook-like, anteriorly and posteriorly distinctly 2-rowed, middle portion zig-zag shaped, second part V-shaped; membranelle 3 consistmg of 3 rows of basal bodies, which are arranged densely. Paroral membrane prominent and genus characteristic, about 4/5 of cell length with its posterior end strongly curved.