The Diadematidae are a family of sea urchins.

Their tests are either rigid or flexible and their spines are long and hollow.

[2] Like other sea urchins diadematids are sensitive to touch, light, and chemicals; additionally they do have eyes (eye spots) which is in contrast to other sea urchins.

[4] Media related to Diadematidae at Wikimedia Commons

This article about a sea urchin is a stub.