(Phymosomatoida) (Phymosomatoida) is a biological order of the phylum Echinodermata (Echinoderms) and class Echinoidea (Heart Urchins).
Phymosomatidae
Stomechinidae
Arbacioida
Cassiduloida
Diadematoida
Echinoida
Echinothurioida
Spatangoida
Holectypoida
Pedinoida
Cidaroida
Phymosomatoida
Salenioida
Clypeasteroida
Temnopleuroida