any snail of the subclass Prosobranchia, class Gastropoda. Most of these roughly 20,000 snail species are marine; a few live on land or in fresh water. Many prosobranchs breathe by means of gills, which are located in the mantle cavity in front of the heart; some have a special respiratory structure on the mantle or, in land species, a simple pulmonary cavity. The auricle of the heart is in front of the ventricle. Larval torsion, a trait peculiar to gastropods that results in a 180-degree twisting of the body, produces a figure-eight arrangement of the viscera and nerve cord that persists throughout life. Most species have a proteinaceous or calcareous lid (operculum) on the foot that seals the aperture of the shell when the animal retracts. The sexes are separate.

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  • Prosobranch — Pros o*branch, n. (Zo[ o]l.) One of the Prosobranchiata. [1913 Webster] …   The Collaborative International Dictionary of English

  • prosobranch — noun (plural branchs) Etymology: New Latin Prosobranchia, from proso in front (from Greek prosō forward) + branchia gills (from Greek) Date: 1851 any of a subclass (Prosobranchia) of gastropod mollusks that have the loop of visceral nerves… …   New Collegiate Dictionary

  • prosobranch — pros·o·branch …   English syllables

  • prosobranch — I. ˈpräsəˌbranŋk adjective Etymology: New Latin Prosobranchia : of or relating to the Streptoneura II. noun ( s) Etymology: New Latin …   Useful english dictionary

  • gastropod — /gas treuh pod /, n. 1. any mollusk of the class Gastropoda, comprising the snails, whelks, slugs, etc. adj. 2. Also, gastropodous /ga strop euh deuhs/. belonging or pertaining to the gastropods. [1820 30; < NL Gast(e)ropoda a class of mollusks.… …   Universalium

  • mollusk — molluskan, molluscan /meuh lus keuhn/, adj., n. mollusklike, adj. /mol euhsk/, n. any invertebrate of the phylum Mollusca, typically having a calcareous shell of one, two, or more pieces that wholly or partly enclose the soft, unsegmented body,… …   Universalium

  • Bithynia tentaculata — Conservation status NE[1] …   Wikipedia

  • Prosobranchia — used to be a large taxonomic subclass of snails (gastropod mollusks). However, that version of gastropod taxonomy dates back to the 1920s, and is now considered to be outdated because that subclass has been proven to be polyphyletic; i.e. the… …   Wikipedia

  • Gastropoda — Gastropod Temporal range: Late Cambrian–Recent[1] …   Wikipedia

  • Valvata piscinalis — Photo of a shell of Valvata piscinalis Drawing of a shell of Valvata piscinalis …   Wikipedia

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