A functional integral formulation, used previously to calculate T-c an
d describe normal state proper-ties of the BCS-Bose crossover, is exte
nded to T < T-c. The saddle point approximation is shown to be qualita
tively correct for T much less than T-c for all couplings, in contrast
to the situation above T-c. Several features of the crossover an desc
ribed. The difference between the T = 0 ''pair size'' and the (prefact
or of the T dependent) Ginzburg-Landau coherence length is pointed out
: the two quantities are the same only in the BCS limit. The evolution
of the collective modes from the BCS to the Bose regime is discussed
together with the mixing of the amplitude and phase in the absence of
a particle-hole symmetry.