The field distribution and the spectrum of plasma eigenmodes are determined for a circular hole in a screen having the form of a hyperboloid of revolution. The spectrum of plasmons is obtained for a planar screen with a circular hole. The symmetric mode with m = 1 can be excited in the field of a dipole oriented along the screen plane, whereas the antisymmetric mode with m = 0 can be excited by a dipole perpendicular to the screen plane. (C) 2003 MAIK "Nauka / Interperiodica".