  We consider the consequences of keeping the total surface fixed for a
polydisperse system of $N$ hard spheres. In contrast with a similar model (J.
Zhang {\it et al.}, J. Chem. Phys. {\bf 110}, 5318 (1999)), the Percus-Yevick
and Mansoori equations of state work very well and do not show a breakdown. For
high pressures Monte Carlo simulation we show three mechanically stable
polydisperse crystals with either a unimodal or bimodal particle-size
distributions.
