  Let K(S) be the subgroup of the extended mapping class group, Mod(S),
generated by Dehn twists about separating curves. In our earlier paper, we
showed that Comm(K(S)) and Aut(K(S)) are both isomorphic to Mod(S) when S is a
closed, connected, orientable surface of genus g at least 4. By modifying our
original proof, we show that the same result holds for g at leat 3, thus
confirming Farb's conjecture in all cases (the statement is not true for any g
less than 3).
