arrowworm

from WordNet (r) 3.0 (2006)

arrowworm
    n 1: any worm of the Chaetognatha; transparent marine worm with
         horizontal lateral and caudal fins and a row of movable
         curved spines at each side of the mouth [syn: {arrowworm},
         {chaetognath}]

from The Collaborative International Dictionary of English v.0.48

Arrowworm \Ar"row*worm`\, n. (Zool.)
   A peculiar transparent worm of the genus {Sagitta}, living at
   the surface of the sea. See {Sagitta}.
   [1913 Webster]

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