  The ``MORPHS'' group has obtained an extensive spectroscopic dataset of
galaxies in the fields of 10 rich clusters at $0.37<z<0.56$; the stellar
population properties of about 700 objects have been determined from a detailed
analysis of spectral line strenghts and colours, up to a galactic absolute
magnitude $M_V=-20.3$ mag. Morphological informations for a consistent fraction
of our sample have been previously derived from deep images of the central
regions of these clusters taken with the WFPC-2 on board the HST. Spectral and
morphological features can be compared in order to study the star formation
histories of the different galactic types in clusters; here we show some
preliminary results of this comparison.
