In recent years, the suprasylvian gyrus of the cat has attracted the attention of many neurophysiologists and experimental psychologists and the variety of their interests is reflected in the number of morphological and functional sub- divisions which have been made of it. Some of these subdivisions are shown in Fig. 1. Workcrs concerned with t. hc visual system havc made studies of the third visual area (awa to) on the medial aspect. of thc gyrus, and of the latcral supra- sylvian area on the lateral aspeet, both of which contain representations of the retina (Clare and Bishop, 1954; Hubel...