The Echinoid Directory

• Test of moderate size, depressed with uniformly rounded sides.
• Apical disc large; plating dicyclic.
• Ambulacral zones moderately broad and straight; not expanded adorally.
• Pore-pairs in almost straight columns. Ambulacral plating compound in triads with all three elements extending to the perradial suture. Pore zones expanded adorally into phyllodes. Large primary tubercle to each compound plate with narrow perradial zone of granules at most.
• Interambulacral plates a little wider than tall; dominated by a primary tubercle with a large areole and mamelon. All tubercles perforate and non-crenulate. Adradial and interradial margins of plate with heterogeneous granulation, including small interradial secondary tubercles.
• Peristome large with shallow, open buccal notches.
• Spines unknown.

Middle Jurassic (Bathonian) to Late Jurassic (Oxfordian) of western Europe.

Hemipedina tuberculata Wright, 1860, by subsequent designation of Lambert & Thiery, 1910, p. 197.

• Pomel based this genus on two species, Miocidaris matheyi (Desor, 1857) from the Bathonian, and M. tuberculata (Wright, 1860) from the Oxfordian.

Acroechinoidea, Pedinoida, Pedinidae.

Subjective junior synonym of Caenopedina A. Agassiz, 1869.

Differs from Hemipedina in having large confluent primary interambulacral tubercles and all three elements of each compound ambulacral plate straddled by a large primary tubercle. Differs from the type species of Caenopedina, C. cubensis, only in having much larger mamelons and presumably stouter spines.

Pomel, A. 1883. Classification méthodique et Genera des Échinides vivante et fossiles. Thèses présentées a la Faculté des Sciences de Paris 503, A. Jourdan, Alger, 131 pp.