Abstract
A Monte Carlo simulation of a lattice model of the nematictosmectic-A transition in three dimensions shows a continuous phase transition with the specific-heat exponent α≃0. The order-parameter correlation functions show anisotropic critical behavior in the nematic phase, where the behavior of the correlation functions in the superconducting gauge strongly indicates an isotropic critical point. Several features observed in experiments are qualitatively reproduced in the simulation.