Wordnet 3.0
NOUN (1)
1.
any of several large worms having a broad flattened body with a mat of coarse hairs covering the back;
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]
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