The Echinoid Directory

• Test circular in outline, low hemispherical in profile.
• Apical disc hemicyclic with rather small periproct (< 50% disc diameter).
• Ambulacral plating trigeminate, with pore-pairs in oblique arcs of three, forming wide adradial band; not expanded adorally.
• Primary ambulacral tubercle on every second or third compound plate only, except adorally, where each plate has a tubercle. Broad perradial granular zone at ambitus.
• Interambulacral plates with single large primary tubercle; aboral plates densely granular. On oral surface small secondary tubercles strongly developed on either side of primary.
• Peristome small, without deep buccal notches.
• Spines short and simple.
• Globiferous pedicellariae with single lateral tooth, tubular blade and no neck.

Recent, Philippine Islands.

Echinus armatus de Meijere, 1902, by original designation.

Only the type species.

Camarodonta; Echinoida; Echinometridae.

Monotypic.

Very similar to Sterechinus in appearance but differing from that genus in having pedicellariae with a single lateral tooth. The apical disc of Selenechinus is more compact with a smaller periproct than is typical of Sterechinus. Evechinus has less granular plating and has pore-pairs obviously aligned into vertical columns, with the inner series clearly separated from the others.

Delage, Y. & Herouard, E. 1903. Les Echinodermes. Traite de Zoologie concrete 3, i-x, 1-495, pls 1-53.