  Using a simple picture of the constituent quark as a composite system of
point-like partons, we construct the parton distributions by a convolution
between constituent quark momentum distributions and constituent quark
structure functions. We evaluate the latter at a low hadronic scale with
updated phenomenological information, and we build the momentum distributions
using well-known quark models. The resulting parton distributions and structure
functions are evolved to the experimental scale and good agreement with the
available DIS data is achieved. When compared with a similar calculation using
non-composite constituent quarks, the accord with experiment of the present
calculation becomes impressive. We therefore conclude that DIS data are
consistent with a low energy scenario dominated by composite, mainly
non-relativistic constituents of the nucleon.
