A sand dollar.
any of an order (Clypeasteroida) of flat, round, disklike echinoid echinoderms that live on sandy ocean beds
- Any of various thin circular echinoderms of the order Clypeasteroida, especially Echinarachnius parma, of coastal northern Atlantic and Pacific waters, having a covering of short movable spines.
- The disklike internal skeleton of a sand dollar, having five radially symmetric oblong markings and often a pattern of long narrow holes.
(plural sand dollars)