  We have measured radial velocities for 196 globular clusters (GCs) around
M49, the brightest member of the Virgo Cluster. Combined with published data,
they bring the total number of GCs with measured radial velocities in this
galaxy to 263. Using this sample, we extract the projected kinematics of the
full sample of GCs, and of the separate metal-poor and metal-rich subsamples.
In agreement with previous results for the global GC kinematics based on
smaller datasets, we find that the GC system as a whole exhibits a slow overall
rotation that is due almost entirely to a net rotation of the metal-poor GC
subsystem alone. In a spatial average, the metal-rich GCs shows essentially no
rotation. We note, however, the presence of a well defined grouping of 10
metal-rich GCs that are located at opposite poles along the galaxy's major axis
and which appear to be rotating at nearly 300 km/s about the minor axis. This
grouping may be the relic of a past merger or accretion event. Using a
Jeans-equation analysis, we show that the GC radial velocities alone point
unequivocally (and independently of X-ray observations) to the need for a
massive dark halo associated with M49 and the Virgo B subcluster around it. We
also show that the GC system as a whole is consistent with an almost perfectly
isotropic velocity ellipsoid. M49 is now the second elliptical galaxy (after
M87) for which we have been able to demonstrate velocity isotropy in the
globular cluster system overall, when no division based on GC color or
metallicity is attempted. Thus, the data for these two galaxies lend support
the general assumption of isotropy when using GC kinematics to study the
dark-matter distribution in early-type galaxies. (ABRIDGED)
