Tube feet

Tube feet (technically podia) are small active tubular projections on the oral face of an echinoderm, such as the arms of a starfish, or the undersides of sea urchins, sand dollars and sea cucumbers; they are more discreet though present on brittle stars, and have only a feeding function in feather stars.

They are used to pass food to the oral mouth at the center, and can attach to surfaces.

A starfish that is inverted turns one arm over and attaches it to a solid surface, and levers itself the right way up.

Tube feet allow these different types of animals to stick to the ocean floor and move slowly.

The podium is the tube-shaped structure that protrudes from the body and contains longitudinal muscle only.