192 THE CEREBRUM. 



Martinotti's cells, like those of Golgi, are probably associative 

 in function. 



The Radiations of Meynert (Figs. 58, 59, 60 and 61). The six 

 fiber zones above enumerated have been as fully indicated in 

 speaking of the cell lamination as the limits of this work will 

 allow, but certain fibers, called the fibers of Meynert, need to 

 be mentioned. The radiations of Meynert are strands of fibers, 

 clearly visible in the radiary zone of the cortex, composed of 

 corticifugal and corticipetal fibers. The corticifugal fibers are 

 very largely axones from the pyramids; the incoming fibers of 

 Meynert's radiations rise in other parts of the cortex or in gray 

 matter situated at a lower level. The radiating fibers belong to 

 the following systems, the projection, the association and the 

 commissural. The radiations are distinct as far out as the external 

 layer of large pyramids and the line of Baillarger, hence the name 

 radiary zone; but in certain regions they are much longer and 

 in some parts of the temporal lobe they extend to the stratum 

 zonale of the first layer. In such regions the line of Baillarger 

 divides the radiary zone into two parts and there is no proper 

 supraradiary zone. 



Association Fibers of Meynert. This name is applied to arcuate 

 fibers of large diameter located in the radiary, the Baillargic 

 and the deep part of the supraradiary zone. Owing to condens- 

 ation they form a distinct layer in the fissural walls and floor, but 

 are sparsely scattered in the crown of the gyrus (Campbell). 

 They arch over the medullary projection, crossing Meynert's 

 radiations at right angles. The deeper ones appear to be con- 

 tinuous with certain fibers in the radiations and are probably 

 corticipetal in direction (Kaes and Campbell). Meynert's asso- 

 ciation fibers are said by Vulpius not to be developed before the 

 seventeenth year; and, according to Kaes, are most abundant in 

 the highly developed parts of the brain. 



Atypical Cortex. The decided variations from the typical 

 cortex are found in the visual and olfactory areas. 



Visual Receptive Center (Fig. 60). The cortex in the cuneus 

 and gyrus lingualis presents three marked variations from typical 

 cortex: i. The greatly accentuated line of Baillarger, which 



