Hierarchy classification:

1. top of the aat hierarchies
2. Agents Facet
3. Living Organisms (hierarchy name)
4. living organisms (entities)
5. Eukaryota (domain)
6. Animalia (kingdom)
7. Echinodermata (phylum)

Narrower term/s

• Clypeastroida (order)

Anotations

Scope note:

Members of a class containing around 950 living species of marine invertebrates having a globular or discoid form, and a rigid shell composed of many calcareous plates, in some species covered with projecting spines.