The term area 31 of Mauss refers to a cortical area defined by myeloarchitecture in the anterior cingulate gyrus of the guenon. Mauss noted that, while much of the area coincides with area 32 of Brodmann (guenon) (numbered 25 at the time Mauss wrote), he was sufficiently doubtful as to the relationship to give the myeloarchitectonic area a different number. A footnote also indicates that area 30 of Mauss in the lateral cortical view was incorrectly labeled "31" ( Mauss-1908 ). (The latter is correctly labeled "30" in BrainInfo).