This problem deals with the wave propagation in a solid cylinder of arbitrary cross section of class 6. The Fourier expansion collocation method by Nagaya is used to satisfy the boundary conditions. The frequency equation which is applicable for the irregular shape is derived. Numerical solutions have been carried out for the circular, elliptic and cardioidal cross sections for bones which belong to class 6. The results are tabulated and the frequency spectrum is also presented. © 1989.