orbital region (ARTHRO: Crustacea) That part posterior to the eyes bordered by the frontal and antennal regions.
orbital tooth (ARTHRO: Crustacea) A tooth on the orbital margin.
orchitic a. [Gr. orchis, testis] Of or pertaining to testicles.
order n. [L. ordin, methodical arrangement] A taxonomic group; a subdivision of a class or subclass, containing a group of naturally related superfamilies or families.
ordinal a. [L. ordin, methodical arrangement] 1. Belonging or pertaining to an order. 2. (ARTHRO: Insecta) Crochets of larvae, describing the length or arrangements at the tip. see uniordinal crochets, biordinal crochets, triordinal crochets, multiordinal crochets.
ordinate a. [L. ordin, methodical arrangement] Arranged in rows, such as ornamentations or punctures.
oreillets n.pl. [F. dim. oreille, projection] (ARTHRO: Insecta) Lateral, spinose processes of male Anisoptera and some Zygoptera on the second abdominal tergite, presumed to act as copulatory aids; auricles.
orange rouge (ARTHRO: Insecta) Cells with intracellular tra-cheoles.
organism n. [Gr. organon, instrument] Any individual living thing.
organization center see organizer organizer n. [Gr. organon, instrument] The region of an embryo seeming to control the differentiation and development of other cells; organization center; inductor; evocator.
organ of Bellonci (ARTHRO: Crustacea) Receptors innervated from the medullae terminales of the brain, consisting of ciliated sensory neurons associated with supporting cells, such as glial, bordering and perilemmal cells; has also been called frontal organ, x-organ, rod-shaped organ. see frontal eye complex.
organ of Berlese see mesospermalege organ of Bojanus (MOLL: Bivalvia) A kidney, especially in oysters.
organ of Hicks see sensillum campaniformium organ of Hoyle see Hoyle's organ organ of Johnston see Johnston's organ organ of Kolliker see Kolliker's organ organ of Ribaga see mesospermalege organogenesis n. [Gr. organon, instrument; genesis, beginning] Formation and development of organs in the embryo. organogenetic a.
organogeny see organogenesis organoid n. [Gr. organon, instrument; eidos, kind] The body forming part of the cytoplasm.
organoleptic a. [Gr. organon, instrument; lambanein, to take hold of] Capable of receiving a sensory stimulus.
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