Sorry, been having to read up on these guys (I don't usually bother trying to ID beyond just recognizing them as feather dusters) - this indicates they don't have a true operculum, and I don't see a pseudoperculum in your pic, so that narrows it down to the taxonomic family Sabellidae.
Does the worm have any eyes on the tentacles there? I don't see any compound eyes, but does it have any eyespots? (They'd look like little, dark dots/tiny balls on the tentacles themselves; they can be hard to see when they're on the dark colored portions of the tentacles - for examples, Figures 2B, 2M, 3B, 13F, 16E, 16I, 21F, and 22F; you can see them in others as well, but they're harder to pick out).
If your worm has eyespots, note as much info as you can about them (things like, do they come in groups, pairs, rows, singularly, etc.; where they're found on the tentacles; how close they are to worm's mouth/body on the tentacle; etc.).