. The evidence for a local super-cluster of galaxies, or "supergalaxy," previously derived from studies of the space distribution of bright galaxies and of the apparent distribution of the continuous cosmic radio radiation finds additional support in an analysis of the new Lick-Mt. Wilson-Palomar lists of radial velocities in terms of "supergalactic" coordinates. Two main effects appear to be present: I) A differential rotation effect explainable by the hypothesis of a general rotation of the super-system around a center located in the Virgo cluster; 2) A differential expansion effect explainable by the hypothesis that the expansion rate is small or negligible in the denser central regions and increases asymptotically outwards in regions of decreasing density. A simple model based on these hypotheses accounts quantitatively for the observations and, in particular, for the conspicuous and so far unexplained non-linearity and anisotropy of the velocity field among the brighter galaxies. The rotational velocity at the Galaxy is about 500 km/sec, corresponding to a period of revolution of the order of 1011 years and to a total mass of the super-cluster of the order of 1015 suns, if the distance of the Virgo cluster is 10 megaparsecs (m - M = 30). The velocity dispersion and the luminosity functions of galaxies of various types derived from the residuals of the non- linear, anisotropic velocity-magnitude relation are discussed in an Appendix.