The radial surfaces of constant angular frequency may be connected with the upper rest latitude of the filament bands (or boundaries of large-scale unipolar magnetic regions) and with the separation of the sunspot region and the polar region (polar faculae, etc.). The equator-ward evolution of the rest latitudes observed since cycle 12 may be a forebode of a deep minimum.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html