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.