Honeycombs are regularly arranged networks of tubules in continuity with the T-system of the skeletal muscle fibre. Their occurrence is usually described in pathologically modified or cultivated muscle fibres. Here we describe the occurrence of honeycombs in macroscopic normal muscle fibres of healthy frogs. We characterize their light- and electronmicroscopic features and represent their relationships to motor end plates, fibre nuclei and myofibrils. In these normal muscle fibres of healthy frogs, the honeycombs are connected to subsynaptic folds and the T-system. Their regional occurrence is discussed with respect to regional differences in the regulation of the membrane metabolism. Since we can demonstrate them in healthy animals, we do not see any basis why their occurrence should be related to pathological modifications of the muscle fibre.