Diadematidae

Diadematidae
Diadema setosum in Oman.
Scientific classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Echinodermata
Class: Echinoidea
Order: Diadematoida
Family: Diadematidae
Gray, 1855

The Diadematidae are a family of sea urchins. Their tests are either rigid or flexible and their spines are long and hollow.