![]() ![]() Microscopic detail of a docoglossan radula showing the denticles or teeth ![]() The teeth often tesselate with their neighbours, and this interlocking serves to make it more difficult to remove them from the radular ribbon. In radulae that just sweep, rather than rasp, the underlying substrate, the shaft and cusp are often continuous and cannot be differentiated. The radula comprises multiple, identical (or near-enough) rows of teeth, fine, flat, or spiney out-growths often, each tooth in a row (along with its symmetric partner) will have a unique morphology.Įach tooth can be divided into three sections: a base, a shaft, and a cusp. In the patellogastropods, though, the teeth lost this ability and became fixed. ![]() The radular teeth can generally bend in a sideways direction. It can be likened to a pulley wheel over which the radular 'string' is pulled. It controls the organ's protrusion and return. The odontophore is the eversible, fleshy tongue underlying the radular membrane. The elastic, delicate radular membrane may be a single tongue, or may split into two (bipartite). Some species have teeth that bend with the membrane as it moves over the odontophore, whereas in other species, the teeth are firmly rooted in place, and the entire radular structure moves as one entity. Components Ī typical radula comprises a number of bilaterally-symmetrical self-similar rows of teeth rooted in a radular membrane in the floor of their mouth cavity. The introduction of the term "radula" (Latin, "little scraper") is usually attributed to Alexander von Middendorff in 1847. Predatory cephalopods, such as squid, use the radula for cutting prey. Predatory pulmonate land slugs, such as the ghost slug, use elongated razor-sharp teeth on the radula to seize and devour earthworms. Other predatory marine snails, such as the Conidae, use a specialized radular tooth as a poisoned harpoon. Predatory marine snails such as the Naticidae use the radula plus an acidic secretion to bore through the shell of other mollusks. In most of the more ancient lineages of gastropods, the radula is used to graze, by scraping diatoms and other microscopic algae off rock surfaces and other substrates. The arrangement of teeth ( denticles) on the radular ribbon varies considerably from one group to another. Within the gastropods, the radula is used in feeding by both herbivorous and carnivorous snails and slugs. The radula is unique to the mollusks, and is found in every class of mollusk except the bivalves, which instead use cilia, waving filaments that bring minute organisms to the mouth. It is a minutely toothed, chitinous ribbon, which is typically used for scraping or cutting food before the food enters the esophagus. The radula ( US: / ˈ r æ dʒ ʊ l ə/ plural radulae or radulas) is an anatomical structure used by mollusks for feeding, sometimes compared to a tongue. ![]()
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