[Kingdom] Animalia Linnaeus, 1758 - animals
   Grade Enterozoa
     Grade Cœlomata
       Phylum Echinoderma
         Branch Ambulacrata
           Class Echinoidea (Leske, 1778) - sea urchins and sand dollars
             Grade Autechini
               Branch Petalosticha
                 1 Order Clypeastridæ
                 2 Order Spatangidæ Gray, 1825