IRIS

(Lat), n. f. I(e)'ris. Gen., ir'idos (-idis), i'reos (-is). Gr.,!/> Fr., '., rhizome d'i. varir (4th def.), glaienl bleu (4th def.). Ger., /., Rfgenbogenhant (1st def..,SV/( v/-M (3d def.), tirlm; rt lilie (3 . l. A thin, circular, contractile membrane, hanging vertically like a curtain in tin anterior chamber. It is attached at its periphery tt> tin sele roc or neal margin bv means of the ligniuentiim | tinatum, and perforated near its centre b.v a circular hole called the pupil. It forms the anterior segment of the uveal coat of the eye. Its posterior surface is covered with pigment. It contains a set of circular muscular fibres, the sphincter, which contracts the pupil; and radiating lii.re> of elastic ti ue which dilate the pupil. The i. is of all colors in birds. [F;L,343.] See cut under EYE. 2. A term for any morA, ape; A. at; A, ah; A, all; Ch, chin; Ch. loch (Scottish); [s. 488]