The universality of the fundamental plane of E and S0 galaxies: Spectroscopic data

We present central velocity dispersion measurements for 325 early-type gala xies in eight clusters and groups of galaxies, including new observations f or 212 galaxies. The clusters and groups are the A262, A1367, Coma (A1656), A2634, Cancer, and Pegasus Clusters and the NGC 383 and NGC 507 Groups. Th e new measurements were derived from medium-dispersion spectra that cover 6 00 Angstrom centered on the Mg I b triplet at lambda similar to 5175 Angstr om Velocity dispersions were measured using the Tonry & Davis crosscorrelat ion method, with a typical accuracy of 6%. A detailed comparison with other data sources is made.