Cunina (fig. 66) with more than eight tentacles; Cunoctantha with eight tentacles, four perradial, four interradial.
All rings of the disk concentric, of nearly equal breadth, connected by four interradial beams, perpendicular one to another.
Between these arise four interradial beams, which are united above by an upper square ring.
Three gates of the cortical shell roundish, on the inside with an interradial spine, little broader than the quadrangular arms.
Between the latter four interradial beams arise from the sides in pairs, and the two pairs are connected by a diagonal arch.
No secondary or interradial ribs are interpolated between the four primary.
Lower ring octagonal, with eight peripheral adradial spines, and with four interradial centripetal teeth on the inside.
On the thinly plated under surface of well-preserved specimens of Edrioaster are seen five interradial swellings (fig. 11, B).
These latter are therefore, as their name implies, radial in position; while the basals and orals are interradial.