Comprehensive DescriptionRead full entry
Description of Oxytricha lanceolataHypotrich ciliate, about 100 x 40 microns. Body very flexible, but constant shape, ellipsoid, anterior third part narrowed and slightly contractile, both ends rounded. About 2:1 flattened dorso-ventrally. Macronuclear segments about 21 x 10 microns, lying slightly left of the median. Micronuclei about 3 microns in diameter. Contractile vacuole on the left-hand border, slightly above the middle of the cell, during diastole with 2 inconspicuous channels. Pellicle without subpellicular granules. Cytoplasm colourless, with many 3-8 microns large, colourless globules and 2-7 microns large crystals in the posterior part of the body. Food vacuoles about 10 microns in diameter, with crystalline content. Movement very rapid, sliding hastily to and fro. Adoral zone of membranelles about 30% of body length, cilia of the distal membranelles about 13 microns long. Buccal area small, undulating membranes nearly straight. Frontal cirri slightly enlarged, about 16 microns long. Buccal cirrus inserted near the anterior end of the undulating membranes. All postoral ventral cirri imediately posterior to the proximal part of the adoral zone of membranelles. Transverse cirri enlarged, slightly cup-shaped, about 28 microns long, distinctly projecting beyond the posterior border. Marginal cirri about 13 microns long, left marginal row J-shaped, terminates at the posterior end of the cell, whereas the right one ends at the level of the posterior transverse cirrus. Caudal cirri inconspicuous. Usually 1 caudal cirrus on dorsal kineties 1-3 each, sometimes 2 on each of these kineties. Dorsal cilia about 3-4 microns long. Dorsal kinety 1 slightly shortened anteriorly, kinety 4 terminates at the middle of the cell. The stomatogenesis begins with the formation of a long and narrow oral primordium, which extends from the left transverse cirrus to the posterior postoral ventral cirrus.