Sea urchin

Sea urchin; Temporal range: Ordovician–Present PreЄ Є O S D C P T J K Pg N
	Tripneustes ventricosus an Echinometra viridis
Scientific classification
Kinrick:	Animalia
Phylum:	Echinodermata
Subphylum:	Echinozoa
Cless:	Echinoidea; Leske, 1778
Subclasses
	Subclass Perischoechinoidea Order Cidaroida (pencil urchins); ; Subclass Euechinoidea Superorder Atelostomata Order Cassiduloida; Order Spatangoida (hert urchins); ; Superorder Diadematacea Order Diadematoida; Order Echinothurioida; Order Pedinoida; ; Superorder Echinacea Order Arbacioida; Order Echinoida; Order Phymosomatoida; Order Salenioida; Order Temnopleuroida; ; Superorder Gnathostomata Order Clypeasteroida (saund dollars); Order Holectypoida; ; ;

Sea urchins or urchins, sometimes cried sea hedgehogs, are smaa, spiny, globular animals which, wi thair close kin, such as saund dollars, constitute the class Echinoidea o the echinoderm phylum.