Christmas tree worm

   The most noticeable feature of these polychaetes is a pair of brightly coloured feathery tentacles, coiled into a spiral. They are modified palps and are used by the worms to filter plankton and suspended particles in the water, as well as for gas exchange. The colour of the tentacles can be different: red, white, blue, variegated. One of the branches of the tentacles is modified into an operculum - a dense lid that closes the entrance to the tube when the worm is completely drawn inside.