The Echinoid Directory

• Test large, subglobular.
• Apical disc small and circular, less than one-quarter test diameter; plating hemicyclic with the two posterior ocular plates exsert. Genital plate 2 larger than other genital plates. Periproct opening smoothly oval.
• Ambulacra straight, about half the width of interambulacra. Pore-pairs biserial throughout and expanding slightly adorally into phyllodes. Plate compounding trigeminate in diadematid style with one large element and two small demiplates. Row of 2 or 3 small subequal primary tubercles to each large element in the triad. Remainder of plate with small scattered granules.
• Interambulacral plates very much wider than tall; a small central primary tubercle plus up to 3 or 4 flanking adradial and interradial tubercles almost as large forming a semi-regular row. Tubercles are small compared to plate height and scattered secondaries cover remainder of plate.
• Ambulacral tubercles similar in size to interambulacral tubercles at ambitus; all tubercles perforate and very finely crenulate (where well preserved).
• Peristome about one-third test diameter and more or less flush; circular with small but well defined buccal notches with thickened lip.
• Spines and lantern unknown.

Lower Cretaceous (Albian), USA, Mexico.

Dumblea symmetrica Cragin, 1893, p. 149, by monotypy.

• Only the type species.

Euechinoidea, Echinacea, unnamed family (pedinopsids).

Monotypic.

Very close to Cottaldia but differing in having biserially arranged pore-zones. Close to Pedinopsis but with trigeminate rather than quadrigeminate plating throughout.

Cooke, C. W. 1955. Some Cretaceous echinoids from the Americas. United States Geological Survey, Professional Papers 264-E, 87-112, pls 18-29.

Cragin, F. W. 1893. A contribution to the invertebrate paleontology of the Texas Cretaceous. Texas Geological Survey, Annual Reports, 4 (2), 139-294, pls 24-46.