  Motivated by the recent experiment performed by the Berkeley group [G. E.
Marti {\it et al.}, Phys. Rev. Lett. {\bf 113}, 155302 (2014)], we consider the
dynamics of magnons in a spin-1 spinor-dipolar Bose-Einstein condensate, using
mean-field theory. We show that the effective mass of a magnon is increased by
the magnetic dipole-dipole interaction, as observed in the experiment. The
magnon mass is also decreased by changing the direction of the magnetic field.
The increase and decrease in the magnon mass manifest themselves in the
acceleration of the magnons.
