Could you ID this worm (Hair warm ???)

[Bojan]

Could you ID this worm



I suppose that it hair worm , but i am not sure.

I have many such interesting worms in my refuge with DSB.

This worm do not have any tube.

Most of the live in the sand and search with quite long tentacles (up to 4cm) sand and rocks.

But some of them are also on the glass and Halimeda alga, so it is very easy to find out, that they do not have any tube.