  We combine Sloan Digital Sky Survey spectra of 22,000 luminous, red,
bulge-dominated galaxies to get high S/N average spectra in the rest-frame
optical and ultraviolet (2600A to 7000A). The average spectra of these massive,
quiescent galaxies are early-type with weak emission lines and with absorption
lines indicating an apparent excess of alpha elements over solar abundance
ratios. We make average spectra of subsamples selected by luminosity,
environment and redshift. The average spectra are remarkable in their
similarity. What variations do exist in the average spectra as a function of
luminosity and environment are found to form a nearly one-parameter family in
spectrum space. We present a high signal-to-noise ratio spectrum of the
variation. We measure the properties of the variation with a modified version
of the Lick index system and compare to model spectra from stellar population
syntheses. The variation may be a combination of age and chemical abundance
differences, but the conservative conclusion is that the quality of the data
considerably exceeds the current state of the models.
