Peristome (?), n. [Pref. peri- + Gr. &unr_;, &unr_;, mouth.] 1. (Bot.) The fringe of teeth around the orifice of the capsule of mosses. It consists of 4, 8, 16, 32, or 64 teeth, and may be either single or double.
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2. (Zoöl.) (a) The lip, or edge of the aperture, of a spiral shell. (b) The membrane surrounding the mouth of an invertebrate animal.
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