  Convection in the cores of massive stars becomes anisotropic when they
rotate. This anisotropy leads to a misalignment of the thermal gradient and the
thermal flux, which in turn results in baroclinicity and circulation currents
in the upper radiative zone. We show that this induces a much stronger
meridional flow in the radiative zone than previously thought. This drives
significantly enhanced mixing, though this mixing does not necessarily reach
the surface. The extra mixing takes on a similar form to convective
overshooting, and is relatively insensitive to the rotation rate above a
threshold, and may help explain the large overshoot distances inferred from
observations. This has significant consequences for the evolution of these
stars by enhancing core-envelope mixing.
