  The stellar kinematics of the dwarf elliptical galaxy NGC 4486B have been
measured in seeing sigma_* = .22 arcsec with the Canada-France-Hawaii
Telescope. Lauer et al. 1996, ApJ, 471, L79 have shown that NGC 4486B is
similar to M31 in having a double nucleus. We show that it also resembles M31
in its kinematics. The velocity dispersion gradient is very steep: sigma
increases from 116 +- 6 km/s at r = 2" - 6" to 281 +- 11 km/s at the center.
This is much higher than expected for an elliptical galaxy of absolute
magnitude M_B = -16.8: NGC 4486B is far above the scatter in the Faber-Jackson
correlation between sigma and bulge luminosity. Therefore the King core
mass-to-light ratio, M/L_V = 20, is unusually high compared with normal values
for old stellar populations. We construct dynamical models with isotropic
velocity dispersions and show that they reproduce black hole (BH) masses
derived by more detailed methods. We also fit axisymmetric, three-integral
models. Isotropic models imply that NGC 4486B contains a central dark object,
probably a BH, of mass M_BH = 6^{+3}_{-2} x 10^8 M_sun. However, anisotropic
models fit the data without a BH if the ratio of radial to azimuthal
dispersions is ~ 2 at 1". Therefore this is a less strong BH detection than the
ones in M31, M32, and NGC 3115. A 6 x 10^8 M_sun BH is 9 % of the mass M_bulge
in stars; even if M_BH is smaller than the isotropic value, M_BH/M_bulge is
likely to be unusually large. Double nuclei are a puzzle because the dynamical
friction timescales for self-gravitating star clusters in orbit around each
other are short. Since both M31 and NGC 4486B contain central dark objects, our
results support models in which the survival of double nuclei is connected with
the presence of a BH (e. g., Tremaine 1995, AJ, 110, 628).
