Action potentials of single afferent optic nervefibers were recorded from the fiber endings in the superficial layers of the tectum opticum of Salamandra s. Three layers of optic nerve fiber endings were found: layer 1 units on the very surface of the tectum, the layer of which is quite thin and which showed properties quite different from those known for the most superficial layer (class 1–2 neurons) of the anuran retina; layer-2 neurons which showed a short on-off response to diffuse light-on and light-off; and layer-3 neurons, which exhibited a tonic on or off response to diffuse light-on and light-off. Layer-2 neurons exhibited a subspecialization.The functional properties of the receptive field organization of the different classes of retinal neurons, the relationship between different stimulus parameters (angular velocity, size, contrast, average luminance) and the neuronal responses are described. A qualitative description of some tectal unit types is given.The different classes of neurons are compared with those of other amphibia and fish, and the experimental neurophysiological findings are compared with behavioral findings.