  Nearly singular isothermal mass distributions with small core radii are
consistent with stellar dynamics, lens statistics, and lens models as a model
for E/S0 galaxies. Models like the de Vaucouleurs model with a constant
mass-to-light ratio are not. While the isothermal distributions are probably an
oversimplification, E/S0 galaxies (at least in projection) must have
significant amounts of dark matter on scales of an effective radius.
