434- SPECIAL HISTOLOGY. 



cells, there moreover exist some nerve-fibres ; but which, owing 

 to their delicacy and the ease with which they are destroyed, 

 it is very difficult to trace. Quitting the ferrugineous layer, 

 and forming a continuous plexus, they are distributed in the 

 inner third of the grey lamina among the large cells and their 

 processes ; their mode of termination has escaped my ob- 

 servation, the result of which amounts only to this : 1. that 

 they become finer and paler, decreasing from their original 

 thickness of 0-0012'", ultimately to one of 0-0006'" and 

 0-0004"', their dark outlines also being replaced by a paler 

 contour ; 2. that they certainly do not form terminal loops, such 

 as Valentin and Hyrtl, who have probably mistaken a fine 

 plexus for such, think they have noticed; but becoming 

 isolated, and running in a more straight direction, and almost 

 as pale as the processes of the nerve-cells at the border of 

 the inner third of the grey lamina, are lost towards the middle 

 of it. 



The crura cerebelli are composed of nothing but parallel 

 nerve-fibres, without any admixture of grey substance, cor- 

 responding with those of the medullary substance of the 

 cerebellum itself, as a continuation of which they are to be 

 regarded. 



§ 116. 



Ganglia of the Cerebrum. — The three pairs of cerebral ganglia, 

 the corpora quadrigemina, optic thalami, and corpora striata, all 

 consist ©f bulky collections of grey substance, and of nerve- 

 fibres ; the former of which are in part quite isolated {corpus 

 striatum), in part mutually connected, and with more deeply 

 lj'ing portions of grey substance {thalami optici, corp. quadrige- 

 mina); the latter connect the ganglia, on the one hand, with 

 the cerebellum and medulla oblongata, and on the other with the 

 hemispheres of the cerebrum. 



The corpus striatum contains two large grey nuclei, the 

 nucleus caudatus anteriorly and superiorly, and the n. lenticularis 

 posteriorly and inferiorly, which are, however, connected in 

 front, constituting a single mass; and besides these, the 

 slender n. tceniaformis, with the amygdala external to the 

 lenticular nucleus, and is in connection principally with the 

 basis of the cerebral peduncle or continuation of the pyramid, 



