What is any one of numerous marine gastropods of the genus Turbo or family Turbinidæ, usually having a turbinate shell, pearly on the inside, and a calcareous operculum called?

turbo — Any one of numerous marine gastropods of the genus Turbo or family Turbinidæ, usually having a turbinate shell, pearly on the inside, and a calcareous operculum. (Webster's 1913.)

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