How Different are Normal and Barred Spirals?
  No significant color differences are found between normal and barred spirals over the range of Hubble stages a - ab - b - bc. Furthermore, no significant difference is seen between the luminosity distributions of normal and barred galaxies over the same range of Hubble stages. However, SBc galaxies are found to be systematically fainter than Sc galaxies at 99% confidence. The observation that normal and barred spirals with Hubble stages a - ab - b - bc have indistinguishable intrinsic colors hints at the possibility that the bars in such spiral galaxies might be ephemeral structures. Finally, it is pointed out that lenticular galaxies of types S0 and SB0 are systematically fainter than are other early-type galaxies, suggesting that such galaxies are situated on evolutionary tracks that differ systematically from those of galaxies that lie along the E - Sa - Sb -Sc and E - SBa - SBb - SBc sequences. 
Sidney van den Bergh
astro-ph.CO