  This paper studies the two-component spinor form of massive spin-3/2
potentials in conformally flat Einstein four-manifolds. Following earlier work
in the literature, a non-vanishing cosmological constant makes it necessary to
introduce a supercovariant derivative operator. The analysis of supergauge
transformations of primary and secondary potentials for spin 3/2 shows that the
gauge freedom for massive spin-3/2 potentials is generated by solutions of the
supertwistor equations. The supercovariant form of a partial connection on a
non-linear bundle is then obtained, and the basic equation of massive secondary
potentials is shown to be the integrability condition on super beta-surfaces of
a differential operator on a vector bundle of rank three. Moreover, in the
presence of boundaries, a simple algebraic relation among some spinor fields is
found to ensure the gauge invariance of locally supersymmetric boundary
conditions relevant for quantum cosmology and supergravity.
