With particular attention now being directed to FIG. 9, it will be noted that a four-lobe structure is illustrated, with the fragmentary filamentary member 35 being provided with four equally spaced lobes such as at 36, 37, 38 and 39. Each of the lobes carries a series of indentations as at 40--40 along the surface thereof, with these indentations contributing to the reduction and fibrillation.