- test depressed; coronal plating rigid to slightly flexible especially adapically
- apical disc relatively small; generally hemicyclic with posterior oculars insert; genital plates strongly projecting interradially. Periproctal plating well-developed peripherally
- ambulacral plating trigeminate, with an enlarged element and two smaller demiplates
- pore-pairs uniserial; arranged into weak arcs. May become crowded adorally to form phyllodes
- interambulacral plates usually with multiple subequal tubercles forming a row. If one, then adradial and interradial zones well developed and with secondary tubercles
- sphaeridial pit close to every third pore-pair from peristome to apex
- tubercles perforate and almost always crenulate
- peristome small; buccal notches rounded, with associated tags. Perradial notch also present
- spines verticillate and hollow or with sparse open mesh
- larva with just two arms.
Lower Cretaceous (Aptian) to Recent; worldwide.
|Classification and/or Status
||Euechinoidea, Acroechinoidea, Diadematoida
||Peters, W. K. H. 1855. Ueber die an der Kuste von Mossambique beobachten Seeigel und isbesondere uber die Gruppe von Diademen. Koenig Akademie der Wissenschafteen, Berlin