Kingdom Animalia Linnaeus, 1758 - animals
   Phylum Echinodermata Bruguière, 1789 - echinoderms
     Subphylum Eleutherozoa Bell, 1891
       1 Class Asteroidea Blainville, 1830 - sea stars
       2 Class Concentricycloidea Baker et al., 1986 - sea daisies
       3 Class Ophiuroidea Gray, 1840 - brittle stars and basket stars
       4 Class Echinoidea (Leske, 1778) - sea urchins and sand dollars
       5 Class Holothuroidea (de Blainville, 1834) - sea cucumbers