The authors present a self-diffusion study of long cylindrical micelles of lecithin in an organic solvent. The results are compared with those obtained for similar micelles of CTAB (cethyltrimethylammonium bromide) in brine. Qualitatively they observe a similar behaviour for both systems. The measured self-diffusion coefficient Ds has a power law dependence on the surfactant concentration. However, the exponent, which is salinity-dependent in the CTAB system, is constant and in good agreement with a theory for living polymers in the lecithin system. In the case of very elongated lecithin and CTAB micelles, Ds becomes independent of surfactant concentration.