Ever since F. Klein designed his "Erlanger programm", geometries have been studied in close connection with their groups of automorphisms. It must be admitted that the presence of a large automorphismgroup does not always have strong implications for the incidence-th- retical behaviour of a geometry. For exampl O. H. Kegel and A. Schleiermacher Geometriae Dedicata 2, 379 - 395 (1974)J constructed a projective plane with a transitive action of its...