Echinoid Sea Urchins

Echinoids, also called Sea Urchins, Echinoids are related to Crinoids and Starfish. Echinoids have a five-pointed star on their back. Live sea urchins are covered in spines that drop off easily, so the fossils only have the skeleton. There name comes from the Greek 'echinos', meaning 'hedgehog'. 

Kingdom: Animalia 
Phylum: Echinodermata 
Subphylum: Echinozoa 
Class: Echinoidea