Kingdom Animalia Linnaeus, 1758 - animals Phylum Echinodermata Bruguière, 1789 - echinoderms Subphylum Eleutherozoa Bell, 1891 Class Echinoidea (Leske, 1778) - sea urchins and sand dollars Subclass Euechinoidea Bronn, 1860 Superorder Gnathostomata Zittel, 1879 1 Order Holectypoida Ducan, 1889 2 Order Clypeasteroida A. Agassiz, 1872 - true sand dollars