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Sea urchin
False fire urchin (Astropyga radiata) in the Philippines.
List of echinoderms
List of echinoderms, An echinoderm is any of more than 6,500 species of invertebrate marine animals belonging to the phylum Echinodermata, characterized by a hard spiny covering or skin. This is a list of significant echinoderms grouped by subphylum and ordered alphabetically followed by a list of extinct echinoderms grouped alphabetically by class. (See also invertebrate.)
subphylum Asterozoa
- brittle star (class Ophiuroidea)
- sea star (class Asteroidea)
- crown-of-thorns starfish (Acanthaster planci)
subphylum Crinozoa
- crinoid (class Crinoidea)
- feather star (order Comatulida)
- sea lily (order Bourgueticrinida)
subphylum Echinozoa
- sea cucumber (class Holothuroidea)
- sea urchin (class Echinoidea)
- cake urchin and sand dollar (order Clypeastroida)
- heart urchin (order Spatangoida)
extinct echinoderms
- blastoid (class Blastoidea)
- genus Cryptoblastus
- genus Pentremites
- carpoid (class Carpoidea)
- cystoid (class Cystoidea)
- genus Echinosphaerites
- sea urchin (class Echinoidea; many extant species)
- genus Holectypus
The Editors of Encyclopaedia BritannicaThis article was most recently revised and updated by Melissa Petruzzello.

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