The Echinoid Directory

• Test globular, flattened below, tall domal above.
• Apical disc small, opening subcircular; dicyclic with genital plate 2 the largest; ocular plates small and projecting only a little.
• Ambulacra trigeminate throughout. Plate compounding arbaciid with large middle element bearing primary tubercle and reduced upper and lower demiplates. Pore-pairs in offset triads forming broad adradial pore band throughout; only the weakest of expansion adorally.
• Ambulacral plates with sometimes one, or two subequal tubercles, or sometimes none on adapical surface; more or less regularly alternating adorally between single and double tubercles; remainder of plate densely covered in uniform small secondaries and granules.
• Interambulacral plates much wider than tall. A small primary tubercle on aboral plates with a few tubercles adradially that are almost as large; the interradial zone is covered in rather dense small secondaries only. At the ambitus and adorally there is an irregular single row of up to 5 subequal tubercles which become offset adradially.
• Ambulacral and interambulacral tubercles of similar size.
• No aboral naked interradial zone, lines of interambulacral tubercles converging adapically.
• Primary tubercles imperforate and non-crenulate in type species.
• Peristome large, flush; buccal notches very feeble, hardly indenting.
• Spines and lantern unknown; no primordial interambulacral plate.

Cretaceous (Aptian) to Eocene; Europe, North Africa.

Echinus rotundus Gras, 1848, p. **, by monotypy.

• C. rotundus (Gras, 1848); Aptian, southern Europe, North Africa.
• C. orbignyi (Cotteau, 1883); Eocene, Spain.

Euechinoidea, Echinacea, Stomechinidae.

The type species has very small tubercles that are imperforate in the type species. However the almost identical Leiopedina has, when well preserved, minute perforations on its tubercles.

Desor, E. 1855-1858. Synopsis des échinides fossiles, lxviii + 490 pp., 44 pls. Reinwald, Paris.

Lambert, J. 1937. Echinides fossiles du Maroc. Notes et Memoires du Service des mines et de la Carte geologique Maroc 39, 1-109.