We present  a synthesis of  recent photometric and kinematic  data for
several of the most dark-matter dominated galaxies. There is a bimodal
distribution  in half-light  radii, with  stable star  clusters always
being  smaller than ~30pc,  stable galaxies  always being  larger than
~120pc.  The larger radius, at  a comparable value of central velocity
dispersion,  implies a larger  mass at  similar luminosity,  and hence
significant dark matter, in dwarf galaxies, compared to no dark matter
in  star  clusters.  We  extend  the  previously  known  observational
relationships and interpret  them in terms of a  more fundamental pair
of intrinsic properties of dark matter itself.