1. Stryker, M. P., and Sherk, H., Science (in the press).
2. Blakemore, C. B., and Van Sluyters, R. C., J. Physiol., Lond., 248, 663–716 (1975).
3. Cragg, B. G., J. comp. Neurol., 160, 147–166 (1975).
4. Buisseret, P., and Imbert, M., J. Physiol., Lond. (in the press).
5. Wiesel, T. N., and Hubel, D. H., J. Neurophysiol., 26, 1004–1017 (1963).