Online Dictionary of Invertebrate Zoology: Complete Work - Best Text

Online Dictionary of Invertebrate Zoology 297discoid a. [Gr. diskos, circular plate; eidos, form] 1. Flat andcircular; disc-like; disciform; discous. 2. (MOLL) Certainunivalve shells with whorls coiled in one plane.discoidal a. [Gr. diskos, circular plate: eidos, form] 1. Approachinga disc in form. 2. (MOLL: Gastropoda) Convoluteor involute and more or less flattend, as the spire of ashell.discoidal area 1. The middle area of an organ. 2. (ARTHRO: Insecta)The middle of a wing; discoidal field.discoidal areolets see discal cellsdiscoidal cell (ARTHRO: Insecta) 1. An outstanding cell of awing. 2. In Odonata, the quadrilateral. 3. In Diptera, themedian cell.discoidal crossvein see discal cross veindiscoidal field see discoidal areadiscoidal triangle see trianglediscoidal vein (ARTHRO: Insecta) 1. In Hymenoptera, the veinforming a continuation of the median vein beyond the endof the transverse median vein, and extending along theposterior margin of the first discoidal cell. 2. In Orthoptera,the first and largest branch of the humeral vein. 3. In Diptera,the media 2 . 4. The anterior intercalary vein.discolor, discolour n. [L. discolor, of different colors] Changeof color; more than one color.discontinued varices (MOLL: Gastropoda) Varices of shellformation when revolution is not in a straight line withthose of the next.discontinuous variation Phenotypic variation in an animalpopulation in which the characters do not grade into eachother; qualitative inheritance. see continuous variation.discooctasters see discoctastersdiscordent margins (MOLL: Bivalvia) Valve margins notmatching, but overlapping one another.discorhabd n. [Gr. diskos, circular plate; rhabdos, rod] (PORIF)A linear spicule with disc-like outgrowths arising from astraight axis.