sea mouse

from WordNet (r) 3.0 (2006)

sea mouse
    n 1: any of several large worms having a broad flattened body
         with a mat of coarse hairs covering the back

from The Collaborative International Dictionary of English v.0.48

Sea mouse \Sea" mouse`\ (Zool.)
   (a) A dorsibranchiate annelid, belonging to {Aphrodite} and
       allied genera, having long, slender, hairlike setae on
       the sides.
   (b) The dunlin.
       [1913 Webster]