Diverse echinoderm faunas consisting of many individuals and many species are found in all marine waters of the world except the Arctic, where few species occur. Echinoids, including globular spiny urchins and flattened sand dollars, and asteroids are commonly found along the seashore. Although many species are restricted to specific temperate regions, Arctic, Antarctic, and tropical forms often are widely distributed; many species associated with coral reefs, for example, range across the entire Indian and Pacific oceans. Many of the echinoderms of Antarctica are distributed around the continent; those with a floating (planktonic) larval stage may be widely distributed, carried ...(100 of 8705 words)