• Webster's Revised Unabridged Dictionary
    • n. pl Peritricha (Zoöl) A division of ciliated Infusoria having a circle of cilia around the oral disk and sometimes another around the body. It includes the vorticellas. See Vorticella.
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Century Dictionary and Cyclopedia
    • peritricha An order of ciliate Infusoria, containing those which have a zone of cilia about the body. These animalcules are free-swimming or attached, solitary or united in social colonies, often in the latter instance forming branched tree-like growths; they have the oral aperture terminal or subterminal; ciliary system consisting of an anterior, circular or spiral, adoral wreath with occasionally one or more supplementary equatorial or posteroterminal locomotive circlets, the remaining cuticular surface entirely smooth. In those instances in which the adoral wreath takes a spiral form the right limb is more usually involute and descending into the oral fossa. The anal aperture is posteriorly located or debouching upon the vestibular or oral fossa. The endoplast is mostly elongate, band-like. These infusorians multiply by longitudinal or transverse fission. There are eight or ten families, all free excepting the Vorticellidæ. See cut under Vorticella.
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Webster's Revised Unabridged Dictionary
NL., fr. Gr. about + , , hair