Expected relation between Vrot/
and ellipticity, for oblate spheroids seen edge on. 
= 0 is for isotropic velocities, while for > 0 is for progressively more anisotropic velocities (less dispersion in the z-direction). As anisotropy increases the lines are lower -- so that a given ellipticity has less and less rotation. The dashed lines show the effects of inclination, moving away from edge on to face on.