  We use the standard, adiabatic shell evolution to predict the size
distribution N(R) for populations of SN-driven superbubbles in a uniform ISM.
We derive N(R) for simple cases of superbubble creation rate and mechanical
luminosity function. We then compare our predictions for N(R) with the largely
complete HI hole catalogue for the SMC, with a view toward the global structure
of the ISM in that galaxy. We also present a preliminary derivation for N(v),
the distribution of shell expansion velocities.
