Crinoid sea lily
Crinoids have a five-fold, or five-sided symmetry and that is what places them in the same family as starfish (with five arms) and sea urchins (with five sides). The stalk, shown here, is composed from a series of plates that sit one on top of the other. The delicate pattern on the surface is to allow one plate to key into the next, giving strength to the stalk.
Find out more on the echinoderms page.