  The spectrum of the integrable spin-S Heisenberg chains is completely
characterized in terms of spin-1/2 spinons. In the continuum limit they form a
quasi-particle basis to the higher level SU(2) Wess-Zumino-Witten (WZW) models.
Enumerating the spinon states in finite systems we obtain effective single
particle distribution functions for these objects which generalize Haldane's
generalized exclusion principle to quasi-particles with non-Abelian exchange
statistics.
