  We employ the previously published neutron scattering experiments\cite{1,2,3}
to suggest that Er$_2$Ti$_2$O$_7$ has a broken-symmetry multiple-{\bf q} state
with tetragonal magnetic symmetry\cite{4}. The ordered moments do not appear to
lie close to the crystal-field anticipated directions\cite{5} and we suggest
that the low energy gapless mode, visible in specific-heat
measurements\cite{6}, is not of the usual transverse isotropic Goldstone-mode
type, but is longitudinal and is associated with the internal transfer of
magnetism between distinct magnetic Bragg spots.
