The term area 8 of Brodmann (guenon) refers to a cytoarchitecturally defined portion of the frontal lobe of the guenon. Located rostral to the arcuate sulcus, it was not considered by Brodmann-1909 to be topographically homologous to the area 8 of Brodmann (human). Distinctive features ( Brodmann-1905 ): compared to area 6 of Brodmann (guenon), area 8 has a diffuse but clearly present internal granular layer (IV);sublayer 3b of the external pyramidal layer (III) has densely distributed medium sized pyramidal cells; the internal pyramidal layer (V) has larger ganglion cells densely distributed with some granule cells interspersed; the external granular layer (II) is denser and broader; cell layers are more distinct; the abundance of cells is somewhat greater.