Crinoids are echinoderms which are closely related to starfish, Sea Urchins and brittle stars. Some of the Crinoids which are found till today have evolved some 420 million years ago. By studying Crinoids, a relation can be established in terms of evolutionary changes that have occurred or have been adopted by the species itself during a certain course of time. Also a relations could also be established to work out the changing climatic conditions since 420 million years ago.