Fig. 2From: A fossil crinoid with four arms, Mississippian (Lower Carboniferous) of Clitheroe, Lancashire, UKSchematic diagram of the cup plating of the monobathrid camerate crinoid Amphoracrinus sp., RGM.1332253. Basals three and low; radials five and with the primanal (X) in the circlet in the CD interray. There is no arm developed in the B ray. Key: A–E = Carpenter raysBack to article page