f the device shown in FIGS. 6 and 7.FIG. 9 is a perspective view of yet another embodiment of an octagon shaped arming device of the present invention and shows, in phantom, distortion of the arming device to cause longitudinal separation of a member of a biopsy instrument.FIG. 10 is a perspective view of the arming device shown in FIG. 9 detached from the biopsy instrument.DESCRIPTION OF THE PREF