Velocity histograms for the 25 sources investigated. For systems consisting of more than one galaxy, a Gaussian with mean and standard deviation corresponding to the derived systemic velocity (C_BI) and dispersion (S_BI) is also plotted. Unshaded portions of the histograms represent foreground and background galaxies. In the cases of B2 1322+36 and 3C 305, the radio galaxy lies just outside of the 3 σ–clipped group. For these two fields, the histogram for the adjacent group is left unshaded, while the radio galaxy is shaded. In all of the histograms, the velocity of the radio galaxy is marked with an arrow.