What is "sea mouse"

Sea mouse \Sea" mouse`\ (Zo["o]l.)

1. A dorsibranchiate annelid, belonging to Aphrodite and allied genera, having long, slender, hairlike set[ae] on the sides.

2. The dunlin.

n. 1 A marine polychaete worm (genus (taxlink Aphrodita genus noshow=1)) with the body covered in a dense mat of setae. 2 The dunlin.

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