  We have simulated lattice QCD directly in the chiral limit of zero quark mass
by adding an additional, irrelevant 4-fermion interaction to the standard
action. Using lattices having temporal extent of six and spatial extents of
twelve and eighteen, we find that the theory with 2 massless staggered quark
flavors has a second order finite temperature phase transition. The critical
exponents $\beta_{mag}$, $\delta$ and $\nu$ are measured and favour tricritical
behaviour over that expected by universality arguments. The pion screening mass
is consistent with zero below the transition, but is degenerate with the
nonzero $\sigma(f_0)$ mass above the transition, indicating the restoration of
chiral symmetry.
