The Echinoid Directory

• Test cordate with weakly convex oral surface and deep frontal sinus.
• Apical disc ethmophract with four gonopores (genital plate 2 separating posterior genital plates and reaching ocular plate IV; subcentral.
• Anterior ambulacrum wide and sunken from apex to peristome; forming prominent notch at ambitus. Pore-pairs differentiated adapically.
• Other ambulacra sunken and petaloid; pore-pairs elongate; petals straight, the posterior pair only slightly shorter than the anterior pair.
• Peristome reniform, with labral plate partially overarching.
• Labral plate relatively long and flask-shaped. Sternal plates unequal with oblique median suture.
• Periproct ovate; high on truncate posterior face.
• Enlarged subanal pore-pairs present.
• Marginal fasciole band crossing plates 4 and 5 in posterior interambulacrum, crossing interambulacra 1 and 4 on plates 4 and 5 and crossing interambulacra 2 and 3 on plates 4 and 5. Second peripetalous band present in lateral interambulacra.

Upper Cretaceous (Cenomanian - Turonian), North Africa, Portugal.

Polydesmaster fourtaui Lambert, 1920, p. 16, by original designation. Syntype: Museum National d\'Histoire Naturelle, Paris, J01261.

• P. fourtaui Lambert, 1920; Cenomanian, Algeria.
• P. tentugalensis (Soares & Devries, 1967); Cenomanian, Turonian, Portugal.

Spatangoida, stem group Paleopneustina.

Unknown.

Differs from all other Paleopneustina except Periaster in having an ethmophract apical disc. Periaster is distinguished because its lateroanal and peripetalous branches coalesce to give rise to a single anterior fasciole.

Lambert, J. 1920. Sur quelques genres nouveaux d\'echinides. Memoires de la Societe academique de l\'Aube 8, p. 145-167, 2 pls.