Figure 4. (1–5) Sinopetalocrinus involutus Mu and Lin, 1987, NIGP 73967, NIGP 73968, NIGP 73969, NIGP 73970 and NIGP 163729; a, oral side of arm plate; b, aboral side of arm plate; c, lateral view of arm plate; d, front view of distal furrows; e, facet view of arm plate. Scale bar = 1 cm.