  We generalize to the supersymmetric case the representation of the KP
hierarchy as a set of conservation laws for the generating series of the
conserved densities. We show that the hierarchy so obtained is isomorphic to
the JSKP of Mulase and Rabin. We identify its ``bosonic content'' with the
so-called Darboux-KP hierarchy, which geometrically encompasses the theory of
Darboux-B\"acklund transformations, and is an extension both of the KP theory
and of the modified KP theory. Finally, we show how the hierarchy can be
linearized and how the supersymmetric counterpart of a wide class of rational
solution can be quite explicitly worked out.
