Crinoid sea lily
This crinoid, Marsupites, has a relatively large, bulbous body (the calyx) which might have been partly buried when the creature was alive, increasing its fossilisation chances. The long arms (not preserved here) extended into the water. Some sea cucumbers, another type of echinoderm, live in a very similar way today on the sandy sea bed of Lyme Bay (see lower photo).
Find out more on the echinoderms page.