
The tube feet can be clearly seen on this sea star
'Tube feet' are the many small tubular projections found most famously on the ventral face of a
starfish's arms, but are characteristic of the
water vascular system of the
echinoderm phylum which also includes
sea urchins,
sand dollars and
sea cucumbers and many other sea creatures.
Tube feet function in locomotion and feeding. The tube feet in a sea star are arranged in grooves along the arms. They operate through
hydraulic pressure. They are used to pass food to the ventral mouth at the center, and can attach to surfaces. A sea star that is overturned simply 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 very slowly.
Tube feet consist of two parts: ampulla and podia.
Ampulla contains both circular muscles and longitudinal muscle, whereas the podia contain the latter only.
Podia bears papilla (adhesive glands) which help to attach with the substratum.