  The abundance of elliptical, S0 and spiral galaxies in clusters is presented
as a function of redshift comparing the results of the HST distant cluster
studies with new data at z~0.2 and with the standard local comparison samples.
This analysis confirms and strengthens the conclusion that the proportion of S0
galaxies increases toward lower redshifts at the expense of the spiral
population. The dependence of the relative occurrence of S0s and ellipticals
and of the morphology-density relation on the cluster concentration are also
discussed.
