  Histogram analysis of Monte-Carlo simulation results of the Ising
antiferromagnet on a stacked triangular lattice are reported. Finite-size
scaling estimates for critical exponents suggest $XY$ universality. This result
supports earlier predictions based on symmetry arguments and is in contrast
with a recent suggestion of a new universality class by Bunker {\it et al.}
[Phys. Rev. B {\bf 48}, 15861 (1993)].
