  It is shown that the worldvolume field theory of a single D3-brane in a
supergravity D3-brane background admits finite energy, and non-singular,
abelian monopoles and dyons preserving 1/2 or 1/4 of the ${\cal N}=4$
supersymmetry and saturating a Bogomol'nyi-type bound. The 1/4 supersymmetric
solitons provide a worldvolume realisation of string-junction dyons. We also
discuss the dual M-theory realisation of the 1/2 supersymmetric dyons as finite
tension self-dual strings on the M5-brane, and of the 1/4 supersymmetric dyons
as their intersections.
