Vorticella

from WordNet (r) 3.0 (2006)

vorticella
    n 1: any of various protozoa having a transparent goblet-shaped
         body with a retractile stalk

from The Collaborative International Dictionary of English v.0.48

Vorticella \Vor`ti*cel"la\, n.; pl. E. {Vorticellas}, L.
   {Vorticellae}. [NL., dim. fr. L. vortex. See {Vortex}.]
   (Zool.)
   Any one of numerous species of ciliated Infusoria belonging
   to {Vorticella} and many other genera of the family
   {Vorticellidae}. 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]