Left panel: evolutionary tracks in the HR diagram for 15 M_⊙ at Z = 0.014, beginning their evolution on the ZAMS with initial rotation around 420 km s^-1. The track labelled Single is for an isolate star computed as in Paper I (transport of angular momentum by shear and meridional currents), the track labelled with Binary is for a binary with an initial orbital period of 1.4 days computed with the same transport mechanisms as in Paper I. The models labelled Single+magn. and Binary+magn. are for single and binary stars, respectively, with similar characteristics, but computed with the Tayler-Spruit dynamo. The colour scales as the abundance ratio N/C at the surface normalised to the initial value on the ZAMS. Right panel: evolution of the surface equatorial velocity for the same models as in the left panel. The colour scales as the ratio Ω_c/ Ω_s.