In Reply to: 500th Dive as Merry's Buddy posted by Max Bottomtime on February 16, 2013 at 20:47:13:

Well, good news, at least for the worm. Leslie Harris of the Los Angeles Natural History Museum identified it as a Chaetopterus polychaete. They live in tubes & while they will climb out if threatened (as when a predator crawls inside in search of dinner) they are pretty helpless once they're out. It wasn't that long ago that all Chaetopterus, no matter if they lived in the Arctic or the Red Sea were called Chaetopterus variopedatus. Researchers use to think they were all the same species. Now it's clear that populations in different areas are distinct species but we still don't have a species name for the local one.

The way they feed is pretty interesting. Those 3 round large segments in the middle of the bottom continuously move back & forth to pump water through the tube. The worm creates a sticky mucus net. As the water moves through the net small particles are captured. Periodically the worm rolls up the net & swallows it, feeding on the particles & getting back the energy it spent on the net.