Richness vs. mass scaling relation within r_200, WL. The solid line with yellow shading represents the mean richness-mass model with 68% uncertainty, while the dashed corridor indicates the mean model ±1 intrinsic scatter. The clusters discussed in the text are labeled. O26 is not fit due to its likely contaminated weak-lensing mass. Including it in the sample would not alter the scaling relation. In this plot and in Fig. 8, richness errors are approximated as Gaussian for plotting purposes, although their exact distributions are properly accounted for in the fit (see text for details).