This is an invertebrate annelid animal, a relative of the earthworm. They live inside a tube built by themselves from grains of sand. The front end of their body has a spirally coiled crown of tentacles through which they breathe, and also serves as a filtering apparatus for capturing food. Their rear end is located inside the tube. For the construction of the tube, they come out, surround the opening with a fold containing secretory glands, and place new material around the longitudinal axis. 

They live on rocky and muddy bottoms, and on rocks or stones from shallow waters to great depths. They feed on plankton or remains of other small organisms that they capture with their crown of tentacles. 

There are male and female individuals, and to reproduce they release their gametes into the water, fertilise them and form eggs. From these eggs hatch larvae that float in the water for a while. As they grow, like their progenitors, larvae descend and live attached to the bottom.

Interesting facts

When disturbed, they can detach their crown of tentacles, hide inside the tube and regenerate their crown again.

Conservation status