The Echinacea are a superorder of sea urchins. They are distinguished by the presence of a rigid test, with ten buccal plates around the mouth, and solid spines. Unlike some other sea urchins, they also possess gills. The group is a large one, with species found worldwide. Echinacea are part of Animalia (kingdom), Echinodermata (phylum), Echinozoa (subphylum), Echinoidea (class), Euechinoidea (subclass), Carinacea (infraclass).