Holopodina with Cup composed of fused radials attached by slightly extended base to substrate without articulation or column. Radial cavity mostly wide and deep, radial articular facet narrow. Arms divided at primibrachial 1 or the axillary primibrachial generally interpreted as fused primibrachials 1 and 2. Proximal brachials commonly stout and tumid. All brachial articulations muscular, and all secundibrachials with pinnule. Arms when retracted or coiled form cover over adoral side of cup. Distinct triangular and perforated oral plates. No chambered organ or aboral nerve center.
Hess H. (2011). Cyrtocrinida. In: Hess H, Messing CG, Ausich WI (Eds.), Treatise on Invertebrate Paleontology, Part T, Echinodermata 2 Revised, Crinoidea, vol. 3. University of Kansas Press, Lawrence, Kansas. 180–206.