Kingdom Animalia Linnaeus, 1758 - animals
   Phylum Echinodermata Bruguière, 1789 - echinoderms
     Subphylum Eleutherozoa Bell, 1891
       Class Holothuroidea (de Blainville, 1834) - sea cucumbers
         1 Subclass Dendrochirotacea
         2 Subclass Aspidochirotacea
         3 Subclass Apodacea