THE CRUSTA OF THE CEREBRAL PEDUNCLE AND ITS GANGLIA. 417 



large quantity of medullary fibres traversing them. This arises 

 from the fact that the third segment is traversed only by 

 fasciculi originating in itself, and has a larger quantity of grey 

 matter (since it is the base of the cone), whilst the internal 



Fig. 245. 



Fig. 245. Transparent transverse section from the region of the 

 Insula and of the principal ganglionic masses (from the brain of Man, 

 slightly enlarged). J J', cortex and medulla of the Insula ; Cl, claus- 

 trum, with clumps of transition-formations between the base of the 

 claustrum and the amygdaloid nucleus ; F, the grey matter of the third 

 ventricle ; L\ Lz Ls, the lenticular nucleus ; N C, the caudate nucleus ; 

 B, the basal portion of the caudate nucleus ; V C, anterior commissure ; 

 J K, region of the internal peduncle (Stiel), and, a K, region of the 

 upper peduncle of the optic thalamus ; M t pes of the corona radiata 

 (Stabkranzes) ; Ce, external capsule ; Ci, internal capsule ; Schl, L, 

 8t, Z, the four layers of the substantia imiominata, or of the loops of 

 the crus cerebri ; G, descending cms of the fornix ; A, commissure in 

 the central grey substance of the ventricle ; 11, optic nerve, with the 

 optic basal ganglion lying upon it. 



segments, in addition to those fibres which originate in them- 

 selves, are traversed by the fasciculi of the third segment on 

 their way to the crus cerebri. Just as the caudate nucleus 



VOL. II. E E 



