PLANETARY-NEBULAE AS PROBES OF DARK-MATTER IN NGC-3384

We have obtained radial velocities of 68 planetary nebulae (PNs) surro unding the SB0 galaxy NGC 3384 in the Leo I group, using the CTIO 4 m telescope and the Rutgers Fabry-Perot interferometer. The PN system ex hibits a well-ordered rotation field aligned with the photometric axes of the galaxy. The rotation curve is flat from about 2 kpc until at l east 7 kpc. We infer a lower limit of 0.7 x 10(11) M. for the mass of NGC 3384. Our results imply that at least a third of the dynamical mas s of the NGC 3379/3384 system-estimated by Schneider (1985) to be roug hly 6 x 10(11) M.-may be accounted for in the two bright galaxies.