Sea-urchins of the Order Diadematoidea with a fully radial symmetrical test without depressions or pits. The tubercles are smooth. The ambulacral plates have more than 3 pore pairs. The gill-cuts are small and inconspicuous. Globiferous pedicellariae lack lateral teeth to jaw-blades which are distinctively tubular. The spicules of globiferous pedicellariae and tube-feet are C-shaped, with the ends branched.
In the North Sea only one species of this family is found in the North Sea:
- Strongylocentrotus droebachiensis