  Non-Markovian transport equations for nuclear large amplitude motion are
derived from the collisional kinetic equation. The memory effects are caused by
the Fermi surface distortions and depend on the relaxation time. It is shown
that the nuclear collective motion and the nuclear fission are influenced
strongly by the memory effects at the relaxation time $\tau \geq 5\cdot
10^{-23}{\rm s}$. In particular, the descent of the nucleus from the fission
barrier is accompanied by characteristic shape oscillations. The eigenfrequency
and the damping of the shape oscillations depend on the contribution of the
memory integral in the equations of motion. The shape oscillations disappear at
the short relaxation time regime at $\tau \to 0$, which corresponds to the
usual Markovian motion in the presence of friction forces. We show that the
elastic forces produced by the memory integral lead to a significant delay for
the descent of the nucleus from the barrier. Numerical calculations for the
nucleus $^{236}$U shows that due to the memory effect the saddle-to-scission
time grows by a factor of about 3 with respect to the corresponding
saddle-to-scission time obtained in liquid drop model calculations with
friction forces.
