Quasi-elastic light scattering spectroscopy was used to measure the mutual diffusion coefficient, D-m, of Triton X-100 micelles in aqueous solution and the translational diffusion coefficient, D-p, of mesoscopic probes in the same solutions. We apply conventional hydrodynamic treatments of diffusion under the assumption that Triton X-100 minimal micelles are adequately represented as hard spheres. D-m and D-p measured at a series of surfactant concentrations are used to infer the micelle radius, fa alpha(m), aggregation number, N, and degree of hydration, delta, for temperatures 10 less than or equal to T less than or equal to 50 degrees C. As T is increased toward the cloud point, alpha(m) and N increase, the increase in N being especially dramatic above 40 degrees C. delta at first increases but then tends to saturate with increasing T.