Illustration of a Crinoid, (Calliocrinus cronutus). Middle Silurian crinoid (Calliocrinus cronutus) based on fossils from the Racine Dolomite of the Chicago-Milwaukee area. Although they resembled flowers and are sometimes called "sea lilies," crinoids are animals related to starfish. With a net of delicate, feathery arms splayed out in the current, crinoids were able to trap microscopic food particles. The food was transported down the arms into the mouth, centrally located on the bulb-like calyx. The anus was also located on the calyx, often elevated by a chimney-like tube and oriented down current to carry away waste products. The long stem-like column served to lift the animal above the seafloor, exposing it to currents for feeding. Most crinoids had a root-like holdfast to secure the animal to the substrate.