290 



ANATOMY OF THE CENTRAL NEETOUS SYSTEM. 



it there is met, as a glance at Fig. 183 shows, the corpus geniculatum laterale and 

 the corpus geniculatum mediale. 



The geniculatum mediale lies in a direct line with the nucleus ventralis thai- 

 ami. Toward the median line it has the fiber-systems of the fillet, with whichj in 

 these planes, are now associated fibers from the roof of the midbrain. 



In the ventral territory of the geniculatum laterale the tractua opticus becomes 

 almost entirely lost, with the exception of single bundles that pass over the genic- 

 ulatum mediale to the stratum, zonale of the corpora quadrigemina. 



The pes pedunculi and the tegmentum are now fully developed. They will be 

 more thoroughly described in the next chapter. 



Fissura cent. 

 Gyrus cent. 



Gyms cent. I - 

 aiit. 



Gyrus cinyul 



Tape turn 

 Fas.Jola / 

 cinereii J 



Spleniutn i 

 Corp. callos. 

 Pulviriji 



Epiplij- 



Corp. genie. 1 

 med, J 



Aquxdnctnf--. 



Corp. geiiic") . 

 lat. ] 



Tegmentiuii"" 



Fes pedun- 

 culi 



Gyms lin- '. 

 guahs / 



f Frisc. long, 

 i inf. 

 ( Rjid. occip.- 

 { thalani. 



{Gyrus fnsi- 

 formis 



Fig. 186. 



In this plane all three nuclei receive their afferent fibers from the corona 

 radiata. The optic radiation, radiatio thalamo occipitalis, and the pathway from 

 the temporal lobe to the geniculatum mediale, which Avas designated as the pedicle 

 (StieJ) of the same in a previous illustration, are now plainly visible. 



In its dorsal region the white medullary substance principally contains fibers 

 of the corpus callosum and short association-fibers. Of the long pathways, the fas- 

 ciculus arcuatus can, perhaps, be traced here. In its ventral half the white matter 

 consists principally of the fiber-systems that arise from the occipital lobe, \\'hich are 

 either fibers belonging to this lobe itself or coronal fibers to the thalamus and to the 

 lateral bundle of the pes. At about one-fourth the distance from the base of the 

 section lies the radiatio occlpito-temporalis, or fasciculus longitudinalis inferior. 



