Figure 7. Generic diversity of crinoids through the Phanerozoic showing the relative proportions of taxa possessing locomotory traits (red) and those lacking such traits (black). Locomotory traits include muscular arm articulations with a well-developed fulcral ridge, fulcrum-bearing cirri distributed along the length of the stalk, absence of a cementing or root-like mode of attachment: for the Paleozoic, this includes only some cladid genera, while for the Mesozoic and Cenozoic, the comatulids, isocrinids, and holocrinids. Generic data from Sepkoski (2002) and Webster (2003).