The experimental data on the hydrogenolysis of long-chain alkanes over suspended cobalt Fischer-Tropsch catalysts are presented which demonstrate the specific character of the molecular-mass distribution of its products (the combination of excess methane, local minimum at C-3-C-7 carbon chain lengths, and local maximum at C-12-C-16 carbon chain lengths). These results provide the experimental verification for the model of the mentioned distribution previously advanced by the authors which includes the hypothesis that the probability of C-C bond cleavage in an alkane molecule increases from the chain center to its ends. These distribution features are observed in the conversion of both alkanes of the suspension medium and individual n-alkanes (n-C16H34) at different temperatures for in situ synthesized nanosized catalysts and commercial oxide samples and for n-C16H34 after distillation of the hydrocarbon medium of the preliminarily suspended nanosized catalyst.