The Echinoid Directory

• Test subovate, of small to medium size, broad with greatest width posterior to centre; oral surface slightly sunken towards the peristome.
• Apical system central, tetrabasal, with four gonopores, complementary plate(s), posterior oculars elongate, reaching periproct (primitive form).
• Petals weakly bowed, long, extending two-thirds of the way to ambitus, poriferous zones narrowing distally but remaining open, inner pore round, outer pore greatly elongated transversely; all ambulacral plates with double pores.
• Periproct aboral, opening into deep anal sulcus that extends to the posterior margin; in contact with posterior oculars of apical disc.
• Peristome anterior, pentagonal, depressed, higher than wide.
• Bourrelets slightly developed.
• Phyllodes slightly widened, double pored, with an inner and an outer series of rounded pores in each half ambulacrum.
• No buccal pores.
• No naked zone in posterior interambulacrum orally.

Bathonian, Middle Jurassic of France.

Nucleolites amplus L. Agassiz in Agassiz & Desor, 1847, p. 154; by subsequent designation of Kier, 1962, p. 63. Holotype M9738, Museum of Natural History, Berne.

• Pomel (1883) included five species when erecting this genus: Echinobrissus Terquemi, amplus, Bourguet, Woodwardi, Grisebachii

Irregularia; Neognathostomata; 'clypeid'

Unavailable name, non Notopygus Holmgren 1857 [a hymenopteran]. Subjective junior synonym of Pseudosorella Etallon,1859.

Pomel (1883) separated Notopygus from Echinobrissus because it had the anal sulcus tapering close to the apical disc. He distinguished it from Holcoepygus by the presence of accessory plates and the enlarged genital plate 2 which separates the posterior genital plates.

Holmgren, A.E. 1857. Forsok till uppstallning och beskrifning af de i sverige funna Tryphonider (Monographia Tryphonidum Sueciae). Kongliga Svenska Vetenskapsakademiens Handlingar. N.F.1 (1)(1855), 93-246.

P. M. Kier. 1962. Revision of the cassiduloid echinoids. Smithsonian Miscellaneous Collections, 144 (3) 262 pp.

Pomel, A. 1883. Classification méthodique et Genera des Échinides vivantes et fossiles. Thèses présentées à la Faculté des Sciences de Paris pour obtenir le Grade de Docteur ès Sciences Naturelles 503, Adolphe Jourdan, Alger, 131 pp.