The term area 24ab (alt) refers to the combination of area 24a and area 24b in a parcellation different from their combination as area a24 ( Vogt-2013 ). While the human, macaque, rat and mouse all have areas 24a and 24b, the designation 24ab in the alternative parcellation refers only to their combination in the human and the macaque, presumably because only in those species are both 24a and 24b located adjacent to the genu of the corpus callosum. In the human, area 24a is called 's24ab' for 'subgenual 24ab' and area 24b is called 'p24ab' for 'pregenual 24ab'. In the macaque, the combination is called simply '24ab', a term that in NeuroNames is categorized as a synonym of area a24 as defined for the human in Glasser-2016..