  The structure of square integrable functionals measurable with respect to the
$n-$point motion of the Arratia flow is studied. Relying on the change of
measure technique, a new construction of multiple stochastic integrals along
trajectories of the flow is presented. The analogue of the It\^o-Wiener
expansion for square integrable functionals from the Arratia's flow $n-$point
motion is constructed.
