SUBCLASS EUECHINOIDEA

• Animals Kingdom (Animalia)

• Echinoderms (Phylum Echinodermata

• Sea Urchins and Sea Cucumbers (Subphylum Echinozoa)

• Sea Urchins, Sand Dollars, and Heart Urchins (Class Echinoidea)

• Sea Urchins (Subclass Euechinoidea)

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Subclass Euechinoidea comprises the modern sea urchins, including the familiar regular sea urchins, sand dollars, heart urchins, sea biscuits, and their relatives within the class Echinoidea of the phylum Echinodermata. They are characterized by a rigid calcareous shell, or test, covered with movable spines and equipped with a complex feeding apparatus known as Aristotle's lantern, used for scraping algae, grazing, or processing food. Members of this subclass occupy a wide range of marine habitats, from rocky shores and coral reefs to sandy bottoms and deep-sea environments. Regular sea urchins are generally spherical and graze on algae and other organic material.