"Fossil crinoid. Close-up of a fossilized crinoid from rocks of the Carboniferous period. The crinoids or sea lilies are primitive marine animals related to starfish and sea urchins. They are usually sessile, attaching themselves to rocks by a stem (broken off in this fossil). The stem is attached to a cup-like body or calyx (at right) which bears a crown of long, feathery arms. The animal used these arms for filtering particles of food from the sea. This crinoid is from rocks of the Carboniferous period, 280-345 million years ago. Only a few crinoid species have survived to the present day with some known to inhabit deep Antarctic waters. Magnification: x1 at 35mm size."