Ryan Photographic - Amphinomidae - Sea mice, fire worms
The family Amphinomidae contains 352 species in 48 genera. Their common names of sea mice and fire worms gives some indication of their life styles. Most of them are free-ranging predators, crawling across the bottom using their parapodia (bristled side paddles).
Most possess chaetae (spines on the parapodia) that are reinforced with calcium carbonate. In some species the chaetae are coated with a substance called complanine which is an ammonium salt. If the sharp spines penetrate the skin it causes intense pain. Not surprisingly, this is a major deterrent for predators. The Chloeia species in the photos below are evidence of this. Both species were out in the open, on dark sand or mud, during the day. I never saw them harassed by a potential predator.
Chloeia flava Golden bristleworm
Chloeia flava Golden bristleworm, Rao Island, Morotai, Indonesia P7053767
Chloeia species, Lembeh Straits IMG_6322
Eurythoe complanata Common fire worm
Eurythoe complanata Common fire worm, Sea of Cortez IMG_2723
Hermodice carunculata Fire worm
Hermodice carunculata Fire worm, Cozumel