  In this paper we investigate the relation between the detailed isophotal
shape of elliptical galaxies and the strength of the H beta absorption in their
spectra. We find that disky galaxies have higher H beta indices. Stellar
population synthesis models show that the H beta line is a good age indicator,
hence disky galaxies tend to have younger mean ages than boxy galaxies. We show
that the observed trend can be brought about by a contaminating young
population, which we associate with the disky component. This population need
only account for a small fraction of the total mass, for example if a
contaminating population of age of 2 Gyrs is superimposed on an old (12 Gyr)
elliptical galaxy, then the observed trend can be explained if it contributes
only 10% to the total mass. The size of this effect is consistent with the
estimates of disk-to-total light ratios from surface photometry.
