Paracrinoidea

Belongs within: Pelmatozoa. The Paracrinoidea are a strictly Middle Ordovician group of stalked echinoderms with arms superficially like those of crinoids, but a central theca more similar to those of cystoids and other blastozoans. Characters (from Kesling 1967): Calcareous plates encasing body constituting a theca, not differentiated into dorsal calyx and ventral tegmen; thecal plates… Continue reading Paracrinoidea