The term area 33pr refers to a very thin, narrow strip of midcingulate cortex located ventrally, adjacent to the body of the corpus callosum in the caudal half of the anterior cingulate gyrus. It is bounded dorsally by area a24pr and p24pr, caudally by area RSC and rostrally by area p24. It is topologically equivalent to the combination of area a33' and area p33' as defined by microscopic internal structure ( Vogt-2012, Glasser-2016 ). Defined in the human by multiple criteria, it is fMRI-activated in MATH and THEORY OF MIND tasks. It is deactivated in LANGUAGE and LANGUAGE STORY tasks. Other authors have referred to overlapping parts of the same topological area as 33' and 16 ( Glasser-2016 ). It has no equivalent in the macaque, the rat or the mouse ( Vogt-2016 ).