FIGURE 2. Characters and main parameters of aboral cups, brachials and columnals in Rhizocrinidae and the centrodorsal of Amphorometra. A–B: aboral cup, A: lateral view (b: basal, r: radial, Dc: maximum diameter, Dp: diameter of stalk insertion = proximalmost stalk diameter, Dr: diameter of distal radial circlet, Hc: height), B: distal face of radial circlet [Dc: maximum diameter, Dd: diameter of central cavity,, fr: fulcral ridge, ic: interradial crest, il: inner (adoral) ligament, m: muscular insertion, nc: neural canal, ol: outer (aboral) ligament, Wr: width of radial]; C: muscular synarthrial facet of non-axillary brachial (W: maximum width parallel to fulcral ridge, other abbreviations as in B); D: external face of axillary brachial (H: height, Wd: distal width, Wm: width of articulation with IIBr1, Wp: proximal width); E–F: distal columnal (f: 8-shaped ligament fossa, fr: fulcral ridge, D: largest facet diameter, d: smallest facet diameter, d': mid-height diameter, H: height, rs: rhizoid socket), E: view from articular facet, F: lateral view; G–H: Amphorometra centrodorsal (a: aboral apex, cs: cirrus socket, D: maximum diameter, D': diameter of central cavity, Dcs: diameter of largest cirrus socket, ib: insertion of basal, ir: interradial ridge), G: adoral view, H: lateral view.