Electron micrograph images of fractal soot clusters obtained from a premixed CH4/O-2 flame are analyzed for two, somewhat neglected, morphological parameters : the structural coefficient k(0) in N = k(0)(R(g)/a)(Df) and the perimeter cutoff function h (x) of the cluster density autocorrelation function. We find for our fractal aggregates that k(0) = 1.23 +/- 0.07 and h (x) is well described by a Gaussian or overlapping spheres model.