sea mouse

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun Any of various large marine polychaete worms of the genus Aphrodite, especially A. aculeata, having a flattened elliptic body with overlapping scales covered by long hairs.

from The Century Dictionary.

• noun A marine dorsibranchiate annelid of the family Aphroditidæ.
• noun Same as sand-mouse.

from the GNU version of the Collaborative International Dictionary of English.

• A dorsibranchiate annelid, belonging to Aphrodite and allied genera, having long, slender, hairlike setæ on the sides.
• The dunlin.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A marine polychaete worm (genus Aphrodita) with the body covered in a dense mat of setae.
• noun The dunlin.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun any of several large worms having a broad flattened body with a mat of coarse hairs covering the back