21 Arthroacantha (are-throw-uh-KANTH-uh) 385 million years ago, Ontario, Canada Arthroacantha carpenteri, UMMP 74714 Specimen donased by Joe Koniecki We sometimes call this a sea lily. Even the scientific name, crinoid (CRY-noyd), means “lily shaped.” But it’s actually an animal! This fossil shows the whole animal, with a stalk and multiple arms connected to each side of its body. The feathery arms filtered plankton floating through the water.