The Echinoid Directory

 Cidaroids with:

• Rigidly sutured corona of relatively thin plates; ambulacral plates rather firmly bound to interambulacral plates.
• Apical disc dicyclic.
• Interambulacral plates with single large primary tubercle that is perforate and strongly crenulate; areoles shallow; extrascrobicular tuberculation strongly heterogeneous.
• Ambulacral plating simple throughout; pore-pairs strongly conjugate.
• Spines long and relatively stout with cortex; often spatulate or facetted with the two sides differentiated; usually coarsely thorned.

Lower Jurassic (Pliensbachian) to Eocene, ? Miocene; widespread.

Distinguished from Cidaridae by its strongly crenulate tubercles and from Histocidaridae by its strongly conjugate pore-pairs.

Lambert, J. 1900. Etude sur quelques echinides de l'Infra-Lias et du Lias. Bulletin de la Societe des Sciences naturelles et historiques de l'Yonne 52 [for 1899], 3-57.