Abstract : Local boundary layer approximations of first order are computed for axisymmetric motions which rotate over a rotating disk in the same and opposite directions. The secondary motions, which are produced by the friction forces at the rotating disk, are essentially of pure stagnation type, distorted stagnation type, cell type, and pure wake type. Critical Reynolds numbers of steady laminar motions which are attached to the disk are computed. They reveal stability properties of rotating flows which are of importance in practical applications. (Author)