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A nudibranch 〔Longman Pronunciation Dictionary (2nd edition), ISBN 0-582-36467-1〕 is a member of the Nudibranchia, a group of soft-bodied, marine gastropod mollusks which shed their shells after their larval stage. They are noted for their often extraordinary colours and striking forms. Currently, about 2,300 valid species of nudibranchs are known.〔Gofas, S. (2014). Nudibranchia. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=1762 on 2015-02-12〕 The word "nudibranch" comes from the Latin ''nudus'', naked, and the Greek βραγχια, ''brankhia'', gills. Nudibranchs are often casually called sea slugs, but many sea slugs belong to several taxonomic groups which are not closely related to nudibranchs. A number of these other sea slugs, such as the photosynthetic Sacoglossa and the colourful Aglajidae, are often confused with nudibranchs. ==Distribution and habitat== Nudibranchs occur in seas worldwide, including both the tropics and Antarctica.〔(Nudibranchs ), Fishermen Scuba.〕 Nudibranchs live at virtually all depths of salt water, from the intertidal zone to depths of well over .〔 The greatest diversity of nudibranchs is seen in warm, shallow reefs, although a new nudibranch species was discovered at a depth near .〔(【引用サイトリンク】url=http://www.mbari.org/twenty/biodiversity.htm )〕 Nudibranchs are benthic animals, found crawling over the bottom substrate.〔 The only exceptions to this are the neustonic ''Glaucus'' nudibranchs, which float upside down just under the ocean's surface and the pelagic nudibranch, ''Cephalopyge trematoides'', which swims in the water column.〔 J.E. Steinberg, ''The pelagic nudibranch, ''Cephalopyge trematoides'' (Chun, 1889), in New South Wales with a note on other species in this genus'', Proceedings of The Linnean Society of New South Wales 81:184-192 (1956) () 〕 〔G.M. Mapstone & M.N. Arai, ''Siphonophora (Cnidaria, Hydrozoa) of Canadian Pacific Waters'', (p.33 ). "The best documented predators of pelagic cnidarians from the phylum Mollusca are the neustonic nudibranchs and snails () the pelagic nudibranch ()"〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「nudibranch」の詳細全文を読む スポンサード リンク
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