  In this article we discuss some consequences of the well-known proposition of
Fritz Zwicky [1], published in the nineteen thirties, that Dark Matter `mimics'
the inertia-gravitational behaviour of usual matter. In particular, we consider
some special dynamical regions such as those of the Ring Systems of the gaseous
giants at the edge of the Planetary System. This article is a continuation of
an earlier paper [2], where it was shown that gravitationally interacting
particles may remain near the Lagrange Points L4 and L5 for many thousands of
years. This provides enough time for the Dark Matter, if present there, to
interact with the usual matter. We discuss also a number of questions related
to places which might be considered singular in the mathematical sense.
