  We consider generally-relativistic gauge transformations for the spinorial
fields finding two mutually exclusive but together exhaustive classes in which
fermions are placed adding supplementary information to the results obtained by
Lounesto, and identifying quantities analogous to the momentum vector and the
Pauli-Lubanski axial vector we discuss how our results are similar to those
obtained by Wigner; by taking into account the system of Dirac field equations
we will investigate the consequences for the dynamics: and in particular we
shall address the problem of getting the non-relativistic approximation in a
consistent way. We are going to comment on extensions.
