1932] Poliak: Afferent Fiber Systems, Primate Cerebral Cortex 173 



dividing the upper quadrants from the lower, except the macula, cor- 

 responds with the bottom of the fissura calcarina (in cases with an 

 equal stretch of the striate area in both lips). The most peripheral 

 portion of the retina, the temporal crescent, is projected upon the 

 most anterior portion of the floor and upon both lips of the calearine 

 fissure. Consequently the "peripheral" boundary of the nasal half 

 of the retina corresponds with the boundary of the striate area, lining 

 the fissura calcarina. The validity of the improbable assumption that 

 in the human brain the temporal crescent is entirely accommodated by 

 the lower lip must be determined by future investigations. (Compare 

 Foerster, 1929 ; that the temporal crescent is represented also in the 

 human brain in both lips of the calearine fissure is supported by the 

 case of Balado-Adrogue-Franlve where fibers of the upper lip were 

 interrupted with the resulting inferior crescentic hemianopsia 

 [mainly]). The macula lutea is projected upon the most posterior 

 portion of the fissura calcarina, principally upon the pole of the 

 occipital lobe and, in the monkey, upon the occipital operculum. 

 Between the temporal crescent and the macular cortex the binocular 

 "peripheral" portion of the representation of the retinae is placed. 

 The horizontal meridian dividing the upper quadrants of both hemi- 

 maculae from their lower quadrants corresponds approximately with 

 a horizontal line, which can be imagined as a caudal continuation of 

 the bottom of the calearine fissure encircling the pole of the occipital 

 lobe and stretching across the occipital operculum toward the fissura 

 simialis. It divides the occipital operculum into an upper and a lower 

 half of somewhat unequal size (approximately 80s in fig. 21). The 

 vertical line dividing the left and right halves of both maculae cor- 

 responds in the monkey with the anterior limit of the striate area 

 covering the occipital operculum and stretching approximately parallel 

 to the sulcus simialis {Ss in fig. 21). Here, also, approximately at 

 the midpoint of the oral boundary of the striate area have to be 

 localized the points of fixation {x and y in fig. 23). Since the extra- 

 macular quadrants have in their cortical representation an approxi- 

 mate shape of a crescent which embraces the macular cortex in front 

 and both dorsally and ventrally, the dorsal and ventral horns of this 

 crescent can be imagined as ending in thin, sharp points. The divid- 

 ing line between the left and right halves of the extramacular cortex 

 would therefore be lost or obliterated.^ 



6 Compare the almost identical view concerning the projection of the retina 

 upon the cerebral cortex in the monkey shared by Brouwer-Heuven-Biemond and 

 by Heuven. 



