Any one of numerous species of ciliated Infusoria belonging to Vorticella and many other genera of the family Vorticellidæ. They have a more or less bell-shaped body with a circle of vibrating cilia around the oral disk. Most of the species have slender, contractile stems, either simple or branched. [1913 Webster]

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OXFORD DICTIONARY

vorticella, n. any sedentary protozoan of the family Vorticellidae, consisting of a tubular stalk with a bell-shaped ciliated opening.

Etymology

mod.L, dimin. of VORTEX

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