The Echinoid Directory

• Test small, length slightly greater than width, posterior margin slightly pointed, anterior margin blunted or weakly concave; adapical surface low domed, margin very thick with steep, rounded sides, greatest height anterior at apical system, adoral surface depressed towards peristome.
• Apical system anterior, tetrabasal, with four gonopores.
• Petals very broad, closing distally, equal, petals II, III, and IV extending almost to margin, petals I and V extending over two-thirds distance to margin. Interporiferous zones very wide, tapering distally; pores in each zone widely separated for most of length of zone; pores conjugate, outer pore slit-like, inner pore elongated transversely.
• Periproct inframarginal, oval.
• Peristome anterior, pentagonal, slightly higher than wide.
• Bourrelets forming low mounds.
• Phyllodes well developed, greatly broadened, double pored with dense, well-defined outer series of pore pairs in each half ambulacrum; plus an irregular inner series; interporiferous area very broad.
• Buccal pore pairs small at peristome edge.

Cenomanian (Late Cretaceous) of Lebanon.

Pygurus noetlingi De Loriol, 1899, p. 4, by original designation.

• Only the type species.

Irregularia; Neognathostomata; \'pygurid\'.

Mortensen (1948, p. 165) distinguished Pyguropsis from Pygurus on the basis of its smaller test, proportionally broader petals, and the inframarginal rather than oral location of the periproct. The presence of paired buccal pores (as noted by Kier, 1962) is unusual, as buccal pores are found in all species having single-pored phyllodes, but rarely in species with double pored phyllodes.

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

Loriol, P. de 1902. Notes pour servir à l’étude des échinodermes, 10. 32 pp., 4 pls. Georg, Basle & Genève.

T. Mortensen 1948. A monograph of the Echinoidea: 4 (1): Holectypoida, Cassiduloida. Reitzel, Copenhagen, 363 pp., 14 pls.