  We present a detailed study of the morphological features of 22 rich galaxy
clusters. We systematically compare cluster images and morphological parameters
in an attempt to reliably identify possible substructure in both optical and
X-ray images. To this end, we compute moments of the surface-brightness
distribution to estimate ellipticities, center-of-mass shifts and orientations.
We find important correlations between the optical and X-ray morphological
shape parameters. Most of our clusters (17) have a good 1-to-1 correspondence
between the optical and the X-ray images and at least 9 appear to have strong
indications of substructure. This corresponds to a percentage of about 40% in
good accordance with other similar analyses. Finally, 4 out of 22 systems seem
to have distinct subclumps in the optical which are not verified in the X-ray
images, and thus are suspect of being due to optical projection effects. We
assess the significance of results using Monte Carlo simulations.
