Studies of the internal anatomy of Mississippian camerate crinoids have revealed the presence and plan of groove and ridge networks here interpreted as evidence of former nervous systems in these animals. The inner thecal surfaces of hollow specimens and surfaces of internal chert molds possess radiating networks of grooves and ridges in both the dorsal cup and tegmen that resemble the plan of the aboral and hyponeural nervous systems, respectively, of modern crinoids. The aboral network of camerates radiates from the basal region of the dorsal cup at the point of stem attachment and provides one radially positioned nerve trunk per arm. In addition to the radial trunks, branches are present in each of the five interrays; the pattern in the CD (i.e., posterior) interray is different from the others. Two ring commissures interconnect the radial and interradial nerve trunks. The hyponeural nerve network in the tegmen originates from a ring commissure located near the upper part of the tegmen. From the ring commissure radiate radial and interradial nerve trunks that divide to produce two nerve trunks per arm as in modern crinoids. Raised ridges that define the hyponeural nerve network on the inner tegminal surface are separate from impressions representing the water vascular network.

By analogy to living crinoids, the aboral nerve center in camerates was located in the base of the dorsal cup. The radial portion of the aboral nervous system is judged to have functioned as the main motor network in camerates, innervating arm flexor muscles, pinnules, and arm epidermis, thus controlling the “display” of arms to form an effective filtration baffle. The interradial aboral nerves may have been sensory nerves which were part of an active balance system in these stalked echinoderms. The hyponeural system in camerates, as in living forms, probably acted as a sensory system by innervation of the lateral walls of the tube feet and arms. A third system, the ectoneural system, which lines the ciliated food grooves and gut of living crinoids has not been detected in fossil camerates; however, due to its functional significance, its presence in camerates was very probable.