‖n. pl. [ NL., from Gr. 'a priv. + &unr_;, pl., the gills of fishes. ] (Zool.) A group of annelids, so called because the species composing it have no special organs of respiration. [ 1913 Webster ]

‖n. pl. [ NL. See Tetra-, and Branchia. ] (Zool.) An order of Cephalopoda having four gills. Among living species it includes only the pearly nautilus. Numerous genera and species are found in the fossil state, such as Ammonites, Baculites, Orthoceras, etc. [ 1913 Webster ]

‖n. pl. [ NL., from Gr. 'a priv. + &unr_;, pl., the gills of fishes. ] (Zool.) A group of annelids, so called because the species composing it have no special organs of respiration. [ 1913 Webster ]

‖n. pl. [ NL. See Tetra-, and Branchia. ] (Zool.) An order of Cephalopoda having four gills. Among living species it includes only the pearly nautilus. Numerous genera and species are found in the fossil state, such as Ammonites, Baculites, Orthoceras, etc. [ 1913 Webster ]