  In this paper we study a 1+1 dimensional relativistic parton model for the
structure of baryons. The quarks and anti-quarks interact through a linear
potential. We obtain an analytic formula for the isospin averaged valence quark
distribution in the chiral and large Nc limits. The leading 1/Nc and non-zero
current quark mass corrections are estimated. Then we extend this model to
include `sea' and anti-quarks. We find that the anti-quark content is small at
a low value of Q^2. Using these distributions as initial conditions for Q^2
evolution, we compare with experimental measurements of the structure function
xF_3(x,Q^2) and find reasonable agreement. The only parameters we can adjust
are the fraction of baryon momentum carried by valence quarks and the initial
scale Q_0^2.
