The Echinoid Directory

• Test subglobular, flattened below, gently domed above.
• Apical disc moderately large; dicyclic; plates firmly bound to corona. Genital plates pentagonal with subcentral gonopore; ocular plates smaller and projecting slightly. The inner edge of genital plates raised to form a lip around the periproct. Periproct subcircular. Disc with pustular ornament and sutural depressions.
• Ambulacra straight; pore-pairs small, uniserial; no differentiation of pore-pairs between apical and oral surfaces. Expanded adorally to form phyllodes.
• Ambulacral plating trigeminate; with lowest element largest, the second smaller but also reaching the perradius, and the upper a small demiplate (close to the apex this too reaches the perradius). All compound plates with a large primary tubercle.
• Interambulacral plates wider than tall; with a single large primary tubercle on ambital and oral plates. Above the ambitus there is still a small tubercle, but this is no bigger than the coarse epistromal ornamentation and so the upper surface looks tubercle-free.
• Basal interambulacral plate not preserved.
• Tubercles imperforate and non-crenulate; mamelons massive on ambital plates.
• Peristome circular, slightly sunken; buccal notches distinct and rather sharp; no tag. No primibasal interambulacral plate or tubercle.
• Spines and lantern unknown.

Echinus hieroglyphicus Goldfuss, 1829, p. **, by monotypy.

Carinacea, Echinacea, Arbacioida, Glypticidae.

Presumed monophyletic.

The characteristic epistroma of the type species is less well developed in the Middle Jurassic G. burgundiacus.

Agassiz, L. 1840. Description des Échinodermes fossiles de la Suisse. Partie 2, Cidarides. Mémoires de la Société helvétique des Sciences naturelles, 4, 107 pp., 11 pls.
 

Mortensen, T. 1935. A monograph of the Echinoidea II. Bothriocidaroida, Melonechinoida, Lepidocentroida and Stirodonta. C. A. Reitzel, Copenhagen.