the root (no rank)
Eukaryota (domain)
Metazoa (kingdom)
Echinodermata (phylum)
Echinozoa (superclass)
Echinoidea (class)
Euechinoidea (subclass)
[hide inferior taxa]
Arbacoida (order)
Cassiduloida (order)
Clypeasteroida (order)
Diadematoida (order)
Echinoida (order)
Phymosomatoida (order)
Spatangoida (order)
Temnopleuroida (order)