/euh pis"theuh brangk'/, n.
1. any gastropod mollusk of the order Opisthobranchia, as the sea slugs, sea butterflies, and sea hares, characterized by a vestigial or absent mantle and shell and two pairs of tentacles.
2. of or pertaining to the opisthobranches.
Also, opisthobranchiate /euh pis'theuh brang"kee it, -ayt'/.
[1850-55; < NL Opisthobranchia the subclass; see OPISTHO-, BRANCHIA]

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      any marine gastropod of the approximately 2,000 species of the subclass Opisthobranchia. These gastropods, sometimes called sea slugs and sea hares, breathe either through gills, which are located behind the heart, or through the body surface. The shell and mantle cavity are reduced or lacking in most species. A pronounced twisting of the body, called torsion, characterizes gastropod development. Among opisthobranchs, however, torsion is usually limited, or individuals “detort” at metamorphosis. As a result, the mantle cavity, when present, generally lies at the side or rear of the animal rather than at the front. Each individual opisthobranch is a simultaneous hermaphrodite—i.e., both male and female reproductive organs occur in one individual.

      For more information on the major groups of opisthobranchs, see bubble shell; nudibranch; pteropod; sea hare.

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Universalium. 2010.

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Look at other dictionaries:

  • opisthobranch — noun (plural branchs) Etymology: New Latin Opisthobranchia, from Greek opisthen behind (akin to Greek epi on) + branchia gills more at epi Date: circa 1856 any of a subclass (Opisthobranchia) of marine gastropod mollusks that have the gills when… …   New Collegiate Dictionary

  • opisthobranch — noun Any of a large and diverse group of specialized complex marine gastropods previously united under Opisthobranchia within the Heterobranchia, characterized by two pairs of tentacles and a single gill behind and to the right of the heart …   Wiktionary

  • opisthobranch — opis·tho·branch …   English syllables

  • opisthobranch — o•pis•tho•branch [[t]əˈpɪs θəˌbræŋk[/t]] also o•pis•tho•bran•chi•ate [[t]əˌpɪs θəˈbræŋ ki ɪt, ˌeɪt[/t]] n. ivt any gastropod mollusk of the order Opisthobranchia, characterized by a small or absent mantle and shell and by two pairs of tentacles:… …   From formal English to slang

  • opisthobranch — /əˈpɪsθəbræŋk/ (say uh pisthuhbrangk) adjective 1. of or relating to the Opisthobranchia, an order of marine molluscs having the gills behind the heart and lacking an operculum. –noun 2. a mollusc of the order Opisthobranchia, as the sea hare and …  

  • opisthobranch — I. əˈpisthəˌbraŋk adjective Etymology: New Latin Opisthobranchia : of or relating to the Opisthobranchia II. noun ( s) : a mollusk of the order Opisthobranchia …   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

  • Opisthobranchia — Temporal range: Carboniferous–Recent[1] …   Wikipedia

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

  • Nudibranch — Berghia coerulescens …   Wikipedia

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