We present spectra of nine low-luminosity early-type galaxies ( M _ { B } > -17.5 ) in the Coma cluster .
The spectra , which were obtained with the Multiple Mirror Telescope and cover the spectral region 3300-5350 Å , exhibit a large variation in Balmer line strengths .
In fact the line strength variation among the Coma low-luminosity galaxies is as large as that found among a sample of low-luminosity ellipticals in the Virgo cluster and lower density environments .
When compared to detailed population synthesis models , the variation in Balmer line strengths among the Coma galaxies indicates a range in luminosity-weighted mean age of from \sim 1 Gyr to \sim 12 Gyr .
The two youngest galaxies are shown to be in a post-starburst state , i.e. , they are not simply former spirals whose star formation was recently terminated .
Moreover , the \sim 1 Gyr ages of these two youngest low-luminosity galaxies are similar to those of the brighter post-starburst galaxies in Coma .