Ventral structures of Stephanocrinus angulatus Conrad

The oral, anal, "pore," arm, and plate structures of Stephanocrinus angulatus Conrad are those of a separate order of crinoids, termed Coronata. Each arm is a biserial set of plates with primaxial at base and 9 or 10 biserial armlets alternately branching off the sides. Two cover plates fit above each food groove, and 5 oral plates cover the mouth. The anal opening is covered by 4 unequal pie-shaped plates. "Pores" are absent. The calyx is composed of 3 basals, 5 radials, and 5 interradials. The ornamentation is similar to that of - pore-rhomb cystoids.

This record provided courtesy of AGI/GeoRef.