. F IGURE . 3. Relations between the metallicity and other GC parameters. The open triangles are thick-disk clusters; open circles, old halo clusters; filled circles, young-halo clusters; filled triangles, corona clusters; and crosses, metal-poor clusters with unknown (B–R)/(B+V+R) . Only clusters with R<60 kpc are shown in (c). A sharp jump near [Fe/H]=-1.0 is seen in all plots. discussion in the text | previous figure | next figure .