  We study macroscopic quantum dynamics of a free domain wall in a
quasi-one-dimensional ferromagnet by use of the spin-coherent-state path
integral in {\it discrete-time} formalism. Transition amplitudes between
typical states are quantitatively discussed by use of {\it stationary-action
approximation} with respect to collective degrees of freedom representing the
center position and the chirality of the domain wall. It is shown that the
chirality may be loosely said to be canonically conjugate to the center
position; the latter moves with a speed depending on the former. It is
clarified under what condition the center position can be regarded as an
effective free-particle position, which exhibits the phenomenon of wave-packet
spreading. We demonstrate, however, that in some case the non-linear character
of the spin leads to such a dramatic phenomenon of a non-spreading wave packet
as to completely invalidate the free-particle analogy. In the course of the
discussion, we also point out various difficulties associated with the
continuous-time formalism.
