There are disclosed various dispensing mechanisms for dispensing filamentary material (24) through a catheter (12) into a treatment site of a patient, for example into an aneurysm sack (20) in a patient's vessel (22). In one embodiment the assembly (100) includes a conical material carrier (150) which is substantially aligned with the dispensing direction, thereby avoiding the need to have a rotating carrier. Another embodiment has a carrier (340) which is at least partially cylindrical. The carrier (150, 340) provides for efficient dispensation of filamentary material at substantial dispensing speeds.