Kingdom [Animalia] Linnaeus, 1758 - animals
   Subkingdom Metazoa Haeckel, 1874 see Kingdom Animalia Linnaeus, 1758
     Division Eumetazoa Butschli, 1910 see Subkingdom Eumetazoa Butschli, 1910
       Subdivision Bilateralia
         Phylum Echinodermata Bruguière, 1789 - echinoderms
           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