A catheter for delivering a prosthesis to a treatment site in a body lumen comprises an elongate flexible member and a sheath slidably disposed thereover. A plurality of self-expanding tubular prostheses are carried in axially spaced apart locations along the elongate member, within the sheath. The prostheses may be selectively interlocked with one another and are constrained by the sheath in a radially contracted configuration. The prostheses are separately releasable from the sheath when the sheath is retracted relative to the elongate member. The catheter also has a pusher member slidably disposed along the elongate member within the sheath. The pusher is adapted to move past the prostheses in a first direction without displacing the prostheses, while in a second direction the pusher engages a selected prosthesis so as to move the prosthesis with the pusher to interlock the selected prosthesis with a second prosthesis.