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race n. [F. race; member of the same stock or lineage] A population or aggregate of populations inhabiting a defined geographical and/or ecological region possessing characteristic phenotypic and gene frequencies or features of chromosome structures that distinguish it from other such groups.

racemose a. [L. racemus, bunch] Bunch, as perhaps of grapes.

racemose glands (SIPUN) Glandular structures on each side of the rectum; function unknown; buschelformigen Korper.

rachidian, rhacidian a. [Gr. rhachis, backbone] (MOLL) The median or central tooth on the radula; the rachidian tooth.

rachiform a. [Gr. rhachis, backbone; L. forma, shape] Shaped like a rachis.

rachiglossate, rhachiglossate a. [Gr. rhachis, backbone; glossa, tongue] (Moll) A radula with three longitudinal rows of teeth: one median (may be simple or have several cusps) and two lateral (rake-like with many cusps).

rachis n.; pl. rachides, rachises [Gr. rhachis, backbone] 1. Any of various axial structures. 2. (NEMATA) The central or axial chord in the ovary around which multiple rows of germinal cells are laid down.

radial a. [L. radial, ray] 1. Extending from a center toward the periphery like rays. 2. Pertaining to a radius.

radial n. [L. radial, ray] (ECHINOD) 1. In Crinoidea, any proximal, undivided plate or ray bearing an anal plate. 2. In Asteroidea, a prominent ossicle on the surface in line with the mid-line of the arm; part of the primary surface. 3. In Echinoidea, the ambulacrum.

radial apophysis (ARTHRO: Chelicerata) In Arachnida, a copu-latory organ on the male palp.

radial canal (CNID: Scyphozoa) A canal in the mesoglea of a medusa running from the center to the edge, or at least in part.

radial cell (ARTHRO: Insecta) A cell bordered anteriorly by a branch of the radial vein.

radial gashes (MOLL: Bivalvia) Radial, sharp-edged cuts found on the upper valve of Gryphaeidae.

radial growth (MOLL: Bivalvia) Growth direction outward from the beak to the shell edge; marked by the costa or other ornamentation.

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