Cerianthus is a genus of tube-dwelling anemones in the family Cerianthidae.

Instead they live semi-buried in soft substrate surrounded by a parchment-like tube which they secrete.

Sand grains, debris and shell fragments usually stick to the outer side of the tube.

The tube is flexible and the anemone can extend its tentacles a surprisingly long way.

The inner ring of tentacles surrounds the central mouth and assists in pushing food inside.