The term area PD of Bonin refers to an area of cerebral cortex that von Bonin and Bailey tried unsuccessfully to identify by cytoarchitecture in Macaca mulatta. They provide a detailed analysis of reports by previous authors in support of their contention that it does not exist. It would correspond to area 2 of Brodmann (guenon), and area 2 of Vogts in the guenon and to area PD of Economo-1929 in the human ( Bonin-1947 ).