The organization of connections from area TEO to TE was studied by the use of the anterogrado tracer Phasaclus vulgans leucoagglutinin (PHA-L). Single or, in one case, two small injections of the tracer were made in the lateral pert of TEO. Labeled terminals wore found in restricted regions of TE within two to five dense foci. In these foci, terminals wore distributed beyond the middlo layers to form a columnar duster elongated ver tical to the cortical surface. This specificity of connections may derive from an organization that is feature specific rather than retinotopic.

Single axons reconstructed from the columnar foci showed heterogeneous features in the laminar distribution. Arbors of some axons were localized in the superficial layers, and those of other were in the middle layers.