planarian

from WordNet (r) 3.0 (2006)

planarian
    n 1: free-swimming mostly freshwater flatworms; popular in
         laboratory studies for the ability to regenerate lost parts
         [syn: {planarian}, {planaria}]

from The Collaborative International Dictionary of English v.0.48

Planarian \Pla*na"ri*an\, n. (Zool.)
   One of the Planarida, or Dendroc[oe]la; any turbellarian
   worm. -- {Pla*na"ri*an}, a.
   [1913 Webster]

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