  Using archival data from the Hubble Space Telescope, we study the
quantitative morphological evolution of spectroscopically confirmed bright
galaxies in the core regions of nine clusters ranging in redshift from $z =
0.31$ to $z = 0.84$. We use morphological parameters derived from two
dimensional bulge-disk decomposition to study the evolution. We find an
increase in the mean bulge-to-total luminosity ratio $B/T$ as the Universe
evolves. We also find a corresponding increase in the fraction of early type
galaxies and in the mean S\'ersic index. We discuss these results and their
implications to physical mechanisms for evolution of galaxy morphology.
