Crinoids were so abundant in the Paleozoic era that their remains form vast thickness' of limestone. These great 'forests' of crinoids probably lived in fairly shallow water. Flower-shaped crinoids have blanketed the seas periodically for more than 440 million years. They collect food with their 'arms'. Each arm has a double row of tiny appendages, or 'tube feet', lining a mucus tract that runs down to the mouth.
Crinoids feed by extending their arms to catch particles that float past.
Having caught something, they move it, with their tube feet, up their sticky food grooves and into their mouth. Their menu was limited to organic particles and small organisms suspended in sea water. It shows the cross section star shape remains of fossilised crinoid stems. This is representative of the most common 'crinoid' fossil found on the beach. You can just make out the thicker stems and the thinner fronds.