Let be a nondegenerate real analytic hypersurface in , let , and let consist of the automorphisms of fixing the point . Then, as follows from a theorem of Moser, the real dimension of does not exceed 5. Here it is shown that 1) dimensions 2, 3, and 4 cannot be realized, but for 0, 1, and 5 examples are given; 2) if the point is not umbilical, then consists of not more than two mappings. Bibliography: 4 titles.