Large Clypeaster Echinoid Fossil from Morocco

Description: Well-preserved example of a large echinoid (sea biscuit) of the genus Clypeaster. Many echinoids are commonly known as sand dollars (flattened) or sea biscuits (dome-shaped). Most have tiny spines by which they move through the sediment; some have a somewhat streamlined shape to facilitate their movement. These are too bulky to have traveled that way, and are thought to have used their spines to pole their way through vegetation. Notice that the pores of the ambulacral system by which the urchin moved have been preserved in great detail.