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PLATE XXII. 



Drawings to illustrate the distribution of the different types of cortex in the frontal lobe 

 of Man and the Anthropoid Ape. 



Motor or " precentral " cortex is indicated by cross-hatching, " intermediate precentral " by large 

 dots, "frontal" by tine dots and " prefrontal " by small circles. 



Rol. Rolando. 



C. M. = Calloso-marginal Fissure. 



S. Free. S. = Sulcus Precentralis Superior. 



S. Prec. Inf. = ,, ' Inferior. 



S. F. 1. Frontalis Primus vel Superior. 



S. F. 2. ,, ., Secundus vel Inferior. 



S. F. Med. ,, Medius. 



S. F. Marg. = ,, Marginalis of Wernicke. 



S. 0. T. Orbitalis Transversus. 



S. Fr. Orb. Fronto-orbitalis. 



S. Olf. ,, Olfactorius. 



I. T. R. = Inferior Transverse Fissure of Rolando. 



A. A. S. = Anterior Ascending Limb of Sylvius. 



A. H. S. = Anterior Horizontal ., ,, 



A. S. = Anterior Sylvian Fissure of Ape. The figures are placed on exposed "insular" cortex. 



E. S. = External Sagittal Fissure. 



C. = Suggested hoiuologue of Sulcus Cruciatus. 



Note the similarity in distribution of the ' Intermediate Precentral " cortex in Man and the 

 Ape, and especially how it spreads down on to the Orbital surface. 



Observe that both the "Frontal" and the " Prefrontal " areas are more extensive in Man 

 than in the Anthropoid. 



