The Echinoid Directory

• Test ovate with distinct anterior sulcus; posterior face truncate. Test subquadrate in outline, longer than wide.
• Apical disc ethmophract with four gonopores.
• Anterior ambulacrum sunken; pore-pairs heterogeneous, formed of a mixture of elongate \'petal-type\' pores and smaller circumflexed pore-pairs.
• Other ambulacra petaloid. Anterior petals flexed forwards, with pore-pairs in posterior column much better developed than those in anterior column. Posterior petals much shorter and straighter.
• Peristome subcircular and facing downwards.
• Labral plate relatively large and triangular; longer than wide. Sternal plates subequal.
• Periproct towards top of posterior truncate face.
• No fascioles, although a band of denser and more aligned granules occurs between the ambitus and a zone level with the ends of the petals.
• Aboral tubercles small and scattered; set in a groundmass of fine granules.

The type species comes from the Albian of England.

Hemipneustes greenovi Forbes, 1852, by original designation.

• H. (Enallaster) greenovi (Forbes, 1852); Albian, England
• H. (Enallaster)  obliquatus (Clark, 1915); early Albian, USA

Spatangoida, stem group (toxasterids).

Subjective junior synonym of Heteraster d'Orbigny, 1855.