The substantia gelatinosa contains a number of mechanisms of particular interest to neurobiologists. With the introduction of new techniques, new data are being acquired, however, as the ultrastructural investigations have been few, we carried out such studies on the synaptic glomeruli in the substantia gelatinosa from the sagittal, frontal, and horizontal planes. The sagittal plane proved to be the most suitable for the observation of synaptic glomeruli.