Christmas Tree Worms
Banco Chinchorro, Mexico
The worms' most distinct features are two "crowns" shaped like Christmas trees. Each spiral is composed of feather-like tentacles called radioles, which are heavily ciliated and cause any prey trapped in them to be transported to the worm's mouth. One major difference between Christmas tree worms and other fan worms is that the latter do not have any specialized body structures to plug their tube holes when they withdraw into them.