  We study low energy collective excitations in a trapped superfluid Fermi gas,
that describe slow variations of the phase of the superfluid order parameter.
Well below the critical temperature the corresponding eigenfrequencies turn out
to be of the order of the trap frequency, and these modes manifest themselves
as the eigenmodes of the density fluctuations of the gas sample. The latter
could provide an experimental evidence of the presence of the superfluid phase.
