  We study the effects of negative spatial curvature on the statistics of
inhomogeneities in open cosmological models. In particular we examine the
suppression of large-separation correlations in density and gravitational
potential fluctuations and the resulting suppression of large-angle
correlations in the anisotropy of the microwave background radiation. We obtain
an expression which gives the {\it minimum} amount of suppression of
correlations for any statistical distribution described by a ``power
spectrum''. This minimum suppression requires that the correlations fall off
exponentially above the curvature scale. To the extent that the observed
correlations in the temperature anisotropy extend to large angular scales, one
can set a lower bound to the radius of curvature and hence on $\Omega_0$.
