A ten-parameter Skyrme force, along with a four-parameter delta-function pa
iring force, have been fitted, using the Hartree-Fock-BCS method, to the ma
sses of 1719 nuclei, both spherical and deformed, with an rms error of 0.75
4 MeV. The corresponding value of the symmetry coefficient J is 28.0 MeV, a
nd that of the effective nucleon mass M* is 1.05M.