  The luminosity dependence of kinematical and isophotal properties of
elliptical galaxies is investigated using numerical simulations of galaxy
merging, combined with semi-analytical models of hierarchical structure
formation. Mergers of spiral galaxies as the only formation mechanism for
elliptical galaxies can neither reproduce the kinematical and photometric
properties of very massive elliptical galaxies nor the change from rotationally
flattened disky to anisotropic boxy systems with increasing luminosity. We
present numerical simulations showing that binary mergers of early-type
galaxies open an additional channel for the formation of anisotropic, slowly
rotating and boxy ellipticals. Including this channel in a semi-analytical
model we can successfully reproduce the observed trend that more luminous giant
ellipticals are more boxy and less flattened by rotation. This trend can be
strengthened by suppressing residual gas infall and star formation for galaxies
with stellar bulge masses $M_* \geq 3 \times 10^{10} M_{\odot}$. Hence we
propose that mergers of early-type galaxies play an important role for the
assembly of massive elliptical galaxies.
