ceras

from WordNet (r) 3.0 (2006)

ceras
    n 1: one of the often brightly colored and branching hornlike
         structures on the back of the nudibranch (and other related
         mollusks) that serve as gills

from The Collaborative International Dictionary of English v.0.48

ceras \ceras\ n.
   one of the often brightly colored and branching hornlike
   structures on the backs of nudibranchs and other related
   mollusks that serve as gills.
   [WordNet 1.5]

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