Radula

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radula

[′raj·ə·lə]
(invertebrate zoology)
A filelike ribbon studded with horny or chitinous toothlike structures, found in the mouth of all classes of mollusks except Bivalvia.

Radula

 

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.

References in periodicals archive ?
Shell Length and Preparation and Examination of Radulae
festiva--copulatory spicules and radula--by comparing them with isolated radulae and copulatory spicules of D.
fornicata larger snails had proportionally shorter radulae with disproportionally fewer rows of teeth than smaller animals.
On the basis of differences in size and morphology of radulae and observations of animals in situ, the two Rubyspira species appear to differ in how they feed.
The sequential nature of this mineralization process makes chiton and limpet radulae highly useful as models for the study of matrix-mediated biomineralization, as each phase of mineral deposition can be observed in a single specimen.
gordensis was uncertain because of the high variability of the type species, corroded condition of the material from Peru, and distance from the type locality; no illustrations of shells or radulae from Peru were provided.
Illustrations of chilodontid radulae were given by Troschel (1879, Euchelus), Hutton (1883, Herpetopoma), Odhner (1917, Hybochelus), Thiele (1924, Euchelus, Danilia and Granata), Cotton (1946, 1959, Granata and Herpetopoma), McLean (1970, Mirachelus), Olsson (1971, Turcica), Beu & Climo (1974, Danilia), Quinn (1979, Mirachelus) and Guidastri et al.
Radulae were then transferred to scanning electron microscope (SEM) stubs, laid flat with the teeth upward, and allowed to air dry before sputter coating with platinum for SEM observations.
Radulae have not been isolated for illustration; the radular teeth have either been drawn as part of a histological section or reconstructed from sectioned material.
Figures of radulae given by Orr-Maes (1967) appear to show no obvious differences between the two genera (figs 4G, H and I, representing respectively Pseudodaphnella granicostata (Reeve, 1846) (as Philbertia (Pseudodaphnella) granicostata, Pseudodaphnella rubroguttata (H.
The basic pattern of most radulae consists of several to numerous transverse rows of radular teeth with bilateral symmetry relative to the main axis, supported by a thin radular membrane.