  In this paper a new theory of Dark Matter is proposed. Experimental analysis
of several Galaxies show how the non-gravitational contribution to galactic
Velocity Rotation Curves can be interpreted as that due to the Cosmological
Constant $\Lambda$. The experimentally determined values for $\Lambda$ are
found to be consistent with those expected from Cosmological Constraints. The
Cosmological Constant is interpreted as leading to a constant energy density
which in turn can be used to partly address the energy deficit problem (Dark
Energy) of the Universe. The work presented here leads to the conclusion that
the Cosmological Constant is negative and that the universe is de-accelerating.
This is in clear contradiction to the Type Ia Supernovae results which support
an accelerating universe.
