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''Turbo'' is a genus of large sea snails with gills and an operculum, marine gastropod molluscs in the family Turbinidae, the turban snails.〔Bouchet, P.; Rosenberg, G. (2012). Turbo Linnaeus, 1758. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=151576 on 2012-09-27〕 ''Turbo'' is the type genus of the family. ==Description== The shells of species in this genus are more or less highly conspiral, thick, about 20–200 mm, first whorls bicarinate, last whorl large often with strong spiral sculpture, knobs or spines, base convex, with or without umbilicus. Species in this genus have a round aperture and a solid, dome-shaped calcareous operculum. This circular operculum commences as a multispiral disc, like that of a ''Trochus'', upon the outer side of which is deposited a thin calcareous layer by a lobe of the foot which projects partly over it. This arrangement produces an operculum which exhibits all the whorls beneath, but which is only feebly, or not obviously spiral above, from the more or less general distribution of the calcareous matter. The radula is broad and generally rather short. The median, lateral and marginal teeth are always present, and the formula is invariably ∞.5.1.5.∞. The central teeth contain no cusps. The median tooth consists of a narrow oblong quadrate basal plate, frequently with accessory plates of various forms, to the lower end of which is attached the oval body of the tooth,—a simple plate without cusp, bearing supporting wings at the sides. Frequently the central teeth are asymmetrical in this group. The laterals bear supporting wings at their outer angles, and are various in form, with or without cusps. The inner marginals are very large, with large cusps. 〔 (G.W. Tryon (1888), Manual of Conchology X; Academy of Natural Sciences, Philadelphia ) 〕 The first ''Turbo'' species were found in the Upper Cretaceous, approximately 100 million years ago. 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「Turbo (gastropod)」の詳細全文を読む スポンサード リンク
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