The common name of the sea mouse refers to what external feature that is characteristic of polychaetes?

The common name of the sea mouse refers to what external feature that is characteristic of polychaetes?

The common name of the sea mouse refers to what external feature that is characteristic of polychaetes?
The sea mouse, Aphrodita aculeata is a marine polychaete worm. Its body is covered in a dense mat of chaetae (hairs), from which the name "sea mouse" derives.