What is it? It is an invertebrate (a creature with no backbone). Some had bodies that sat on top of stems which attached to the sea floor. Others attached directly to the sea floor. When did it live? Sometime in a period from 345 to 315 million years ago. Is this type of creature extinct? Yes. They became extinct about 200 million years ago. Where did it live? All of these creatures were marine. They spent their lives attached to the sea floor. How did it eat? What did it eat? Small, hairlike arms swept food into the creatures mouth, which was on the top of its body.