Kingdom Animalia Linnaeus, 1758 - animals
   Phylum Echinodermata Bruguière, 1789 - echinoderms
     Subphylum Echinozoa von Zittel, 1895 see Infraphylum Echinozoa Haeckel, in Von Zittell, 1895
       1 Class Echinoidea (Leske, 1778) - sea urchins and sand dollars
       2 Class Holothuroidea (de Blainville, 1834) - sea cucumbers
       3 Class †Edrioasteroidea Billings, 1858
       4 Class †Ophiocistioidea (Sollas, 1899)
       5 Class †Helicoplacoidea Durham & Caster, 1963
       6 Class †Cyclocystoidea Miller & Gurley, 1895
       7 Class †Edrioblastoidea