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(invertebrate zoology)
A filelike ribbon studded with horny or chitinous toothlike structures, found in the mouth of all classes of mollusks except Bivalvia.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.



an apparatus in mollusks, except bivalves, that rasps off and tears up food. The radula consists of a chitinous basal ribbon that lies on the surface of the tongue, the muscular out growth of the ventral wall of the pharynx. It is covered with cross rows of numerous, up to 75,000, chitinous teeth, the number, shape, and position of which serve as taxonomic criteria. The radula works like a dredge equipped with scoops. Its main function is to allow the mollusk to rasp off the food, which is then swallowed.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
Many subsequent authors perpetuated Lamarck's misidentification, until Clench and Turner (1964) described the radular morphology and properly distinguished both taxa.
Diffferentiation in radular and embryonic characters, and further comments on gene flow, between two sympatric morphs of Littorina saxatilis (Olivi).
Finally, the images were analyzed using the software Image Pro-Plus, version 5.0 (Media Cybernetics, Rockville, MD), to estimate radular length and width.
Radula (Figs 16, 17): rachidian tooth wide, comb-like, occupying about half of radular width; curved base, width ~ 5x greater than its length; ~17 triangular, sharp pointed cusps of similar size, except for some diminishment towards the side; lateral tooth hook-like, bicuspid, base broad (equivalent to 1/2 of rachidian base width), obliquely disposed; main lateral cusp widely curved inwards, about as long as base; secondary, medial cusp approximately half the size of lateral cusp; both cusps separated from each other by smooth area equivalent to 1/3 of tooth's width.
Forewing with yellow or light brown veins and greyish radular areas, membrane colorless, transparent.
Significance of radular characters for reconstruction of thaidid phylogeny (Neogastropoda: Muricacea).
Distribution and radular morphology of various nudibranchs (Gastropoda: Opisthobranchia) from the Gulf of California.
In GKL with an SL of ~2 mm, the teeth are larger, the rachidian tooth no longer has a triangular tip and lies flat along the radular ribbon except for a curled cusp.
In our long-term growth studies, the mesh bags housing the snails might have encouraged the development of biofilms, and thus provided an additional food source for juveniles through radular rasping, particularly for those being maintained without solid substrate (Chaparro et al., 2002; Navarro and Chaparro, 2002).