Echinoida
Echinoida is an order of sea urchins in the class Echinoidea. They are distinguished from other sea urchins by simultaneously possessing both an un-sculpted test and a feeding lantern with large plates fused across the top of each pyramid.
Taxonomy
Order Echinoida- family Echinidae Gray, 1825
- family Echinometridae Gray, 1825
- family Parasaleniidae
- family Strongylocentrotidae Gregory, 1900