What is it? Fossil forms of these invertebrates (creatures with no backbones) had a cup-shaped body, called a crown, with feathery arms extending out from it. The crown sat on top of a stalk or clawlike structure with which the creatures attached to a surface. When did it live? Sometime in a period from 345 to 315 million years ago. Is this type of creature extinct? No. Some types of these creatures live today, mainly in the deep parts of the ocean, but they are not nearly so common as in the past. Where did it live? Most fossil forms of these creatures remained stalked and attached to the sea floor for their entire lives. How did it eat? What did it eat? The creature’s mouth, on top of its crown, has food swept into it by the feathery arms which surround it.