from The Century Dictionary and Cyclopedia
- A family of fossil sea-urchins, or Echinoidea, having very large spine-tubercles decreasing in size toward the poles, ambulacra increasing in width actinally, and few interambulacral plates. Its species occur in the Permian, Jurassic, and Cretaceous rocks.
Sorry, no etymologies found.
Sorry, no example sentences found.