Figure 3.

Topological comparison of the pallial regions of a stem amniote, a generalized extant mammal, and a generalized extant sauropsid, as postulated by Butler.⁹⁰ For this and subsequent figures, the medial pallium, i.e., hippocampal formation, is indicated by light shading, the lemnopallial regions in hatching from upper left to lower right, the collopallial regions in hatching from upper right to lower left, and the piriform cortex in darker shading. The same topological order holds across extant mammalian neocortex and the extant sauropsid dorsal cortex/Wulst and dorsal ventricular ridge sensory-recipient pallial regions. Abbreviations: A, auditory pallium; Ci, cingulate gyrus; Dl, dorsolateral pallium; Dml, lateral part of dorsomedial pallium; Dmm, medial part of dorsomedial pallium; F, frontal neocortex; I, insular cortex; P, piriform cortex; S, subiculum; SM, somatomotor cortex; V1, primary visual cortex; V2, secondary visual cortex. Where abbreviations for mammalian pallial terms, such as cingulate gyrus and insular cortex, are used in the sauropsid diagram, their respective homologues are indicated.