a. [f. mod.L. tetramer-us (ad. Gr. τετραμερής four-parted, f. τετρα, TETRA- + μέρ-ος part) + -OUS.] Having, consisting of, or characterized by four parts. spec. a. Bot. Having the parts of the flower-whorl in series of four. (Often written 4-merous.) b. Entom. Having the tarsi four-jointed, as the Tetramera among Coleoptera. c. Having four rays, as a starfish.
1826. Kirby & Sp., Entomol., III. xxxv. 634. Tetramerous insects are those in which all the tarsi consist of four joints.
1835. Lindley, Introd. Bot. (1848), I. 316. Tetramerous, if [a flower consists of organs] in fours.
1857. Henfrey, Elem. Bot., 230. Papaveraceæ.… Flowers regular, 2-merous or 4-merous.
1859. Darwin, Orig. Spec., vii. (1873), 173. All the other flowers on the plant are tetramerous.
1861. Hulme, trans. Moquin-Tandon, II. III. vi. 157. A tetramerous Coleopter belonging to the family Rhyncophora.
So Tetrameral a., having parts in fours; also, belonging to the Tetrameralia, a subdivision of the Hydrozoa Acraspeda in Claus’s classification; Tetrameralian a. = TETRAMERAL; sb. a member of the Tetrameralia; Tetramere, a division of the fourth order in the supporting reticular skeleton of the extinct siliceous sponges (Cent. Dict. Suppl., 1909); Tetramerism, the condition of being tetramerous; division into four parts or into sets of four.
[1888. Rolleston & Jackson, Anim. Life, 789. I. Tetrameralia: with four radial sectors…. II. Octomeralia: with eight sectors.]
1888. Amer. Nat., XXII. 941. The morphological significance of the primary subdivision into four or tetramerism of the germ-bands of Stenobothrus and Œcanthus.
1899. Syd. Soc. Lex., Tetramerism.
