. Quain's elements of anatomy . e corpuscallosum has beenfully exposed byseparating the ce-rebral hemispheresand throwing themto the side ; the gy-rus fornicatus hasbeen partly de-tached, and thetransverse fibres ofthe corpus callo-sum traced forsome distance intothe cerebral medul-lary substance. 1, the upper sur-face of the corpuscallosum ; 2, me-dian furrow orraphe; 3, longitu-dinal strise boiiad-ing the furrow;4, swelling formedby the transverse bands as they pass into the cerebrum, arching over the side of the lateral ventricle ; 5,anterior extremity or knee of the corpus callosum ; 6, po
. Quain's elements of anatomy . e corpuscallosum has beenfully exposed byseparating the ce-rebral hemispheresand throwing themto the side ; the gy-rus fornicatus hasbeen partly de-tached, and thetransverse fibres ofthe corpus callo-sum traced forsome distance intothe cerebral medul-lary substance. 1, the upper sur-face of the corpuscallosum ; 2, me-dian furrow orraphe; 3, longitu-dinal strise boiiad-ing the furrow;4, swelling formedby the transverse bands as they pass into the cerebrum, arching over the side of the lateral ventricle ; 5,anterior extremity or knee of the corpus callosum ; 6, posterior extremity; 7, anterior,and 8, posterior fibres proceeding from the corpus callosum into the frontal and occipitallobes respectively ; 9, margin of the swelling ; 10, anterior part of the gyrus fornicatus ;11, fissure between the corpus callosum and this convolution opened out; outside 12, isthe termination of the calloso-marginal fissure, and before 13 is the parieto-occipitalfissure; 13, upper surface of the cerebellum. 3-14 THE CEREBEAL HEMISPHERES. Althoogli it lias a few longitudinal wMte fibres on its surface, tlie corpuacallosum consists almost entirely of fibres having a transverse course, andspreading on each, side in a radiating manner into the substance of the hemi-spheres. The greater thickness of the corpus callosum at its anterior and posteriorextremities than in the intervening part is due to the increased aggregation ofthe fibres in the two former situations, and the greater thickness of the posteriorextremity is attributable to the mass of the cerebral hemisphere which is behindthe corpus callosum being larger than that in front. The fibres are arranged in flattened bundles with the long axes of the bundlesvertical but becoming horizontal at the ends. In their passage into the parietallobes and into the posterior part of the frontal lobe their direction is nearlytransverse, but from the genu they curve round into the anterior part of thefrontal lobe, and
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