any of a genus (Vorticella) of one-celled ciliates living in water, with a bell-shaped body on a thin, contractile stem serving as a holdfast
See vorticella in American Heritage Dictionary 4
(vôrˌtĭ-sĕlˈə)
nounpl.vor·ti·cel·lae(-sĕlˈē) or vor·ti·cel·las
Any of various ciliate protozoans of the genus Vorticella, having a bell-shaped body and living underwater on a slender stalk often attached to a plant or other object.