  We find the dyonic worldvolume solitons due to parallel (p,q) strings ending
on a D-3-brane. These solutions preserve 1/4 of bulk supersymmetry. Then we
investigate the scattering of well-separated dyons and find that their moduli
space is a toric hyper-K\"ahler manifold. In addition, we present the
worldvolume solitons of the D-3-brane which are related by duality to the
M-theory configuration of two orthogonal membranes ending on a M-5-brane. We
show that these solitons preserve 1/8 of supersymmetry and compute their
effective action.
