1. Gaze, R. M., and Peters, A., Quart. J. Exp. Physiol., 46, 299 (1961).
2. Nieuwkoop, P. D., and Faber, J., Normal Table of Xenopus Laevis (Daudin), second ed. (North Holland, Amsterdam, 1967).
3. Straznicky, K., and Gaze, R. M., J. Embryol. Exp. Morphol., 26, 67 (1971).
4. Sperry, R. W., J. Comp. Neurol., 79, 33 (1943).
5. Sperry, R. W., J. Neurophysiol., 1, 57 (1944).