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University of California Puhlications in Anatomy [Vol. 2 



lateral ventricle and finally turn down into the upper lip of the fissura 

 ealcarina where they again turn partly oralward (figs. 75, 76). In 

 other words, the dorsal portion of the visual radiation has its own 

 course, remains dorsal during almost its entire course, and does not 

 mix with other portions of the radiation. Neither does it come closer 

 to the ventral lip of the calcarine. fissure, as alleged by some investi- 

 gators, nor does it pass through the thin fiber layer covering the calcar 



Fig. 22. A scheme to show the course and the arrangement of the entire 

 afferent visual path from its beginning in the retina of the eye (left in the 

 figure) to its termination in the occipital lobe (right in the figure). Eight 

 hemisphere of the brain of Macacus viewed from the internal side and imagined 

 transparent. Contours of the hemisphere, of the convolutions and furrows, and 

 of the eye-bulb grey or black ; in the retina, in the optic nerve and optic tract, in 

 the external geniculate body and in the visual radiation green color corresponds to 

 the lower extramacular quadrants, yellow to the lower macular quadrants, 

 blue to the upper extramacular quadrants, pink to the upjier macular quadrants. 

 In the external geniculate body and in the visual radiation the relative posi- 

 tion of various bundles corresponds to their actual position as found in the 

 present investigations (combined with those of Brouwer-Zeeman). Both upper 

 and lower extramacular fibers enter upper and lower lip of the calcarine fissure 

 respectively; macular fibers interposed between both extramacular bundles 

 enter the pole of the occipital lobe and the operculum occipitale. (For explana- 

 tion see Chapter XVI, 2, and Chapter XVII.) 



avis to reach in this way the lower lip. Its fibers in part only, in so 

 far as they are destined for the deeper portions of the upper lip closer 

 to the bottom of the calcarine fissure, penetrate into the calcar avis ; 

 yet they penetrate only from above (figs. 70, 72, 75, 76). Because of 



