142 LECTURES OX THE CENTRAL NERVOUS SYSTEM. 



somewhat farther forward than the one given in Fig. 84. In 

 order to simplify matters the anterior peduncles are represented 

 as occupying a wrong position, as may be seen by comparison 

 with Fig. 84. They ought to be shown lying close over the 

 ventricle. 



The first thing to attract our notice is that the different 

 parts of the cortex are connected by curved fibres, fibrae arci- 

 ibrmes. From all points of the cortex fibres arise, which, 

 diverging from each other like the limbs of a tree, pass into the 

 white substance. They are called the Dendritic tracts. Before 

 they reach the corpus dentatum they are lost in a thick tangle 

 of fibres. Several zones of these tangled fibres can be distin- 

 guished, and, from the fact that a true decussation can be made 

 out in them, they have received the name of decussating zones. 

 External to the ciliary body is a mass of fibres converging 

 toward it, which in part enter the gray matter and in part pass 

 through it. This mass of fibres, on account of its resemblance 



O ' 



to wool, is called the fleece. 



The anterior peduncles enter the ciliary body and break up 

 into a net-work of fibres. This net-work (intra-ciliary fibres) 

 is connected, either directly or by means of ganglion-cells, with 

 the before-mentioned tangle of fibres, the fleece (extra-ciliary 

 fibres). Fibres pass from this intra-ciliary net-work to the 

 anterior peduncles, and to it from the cortex of the hemispheres. 

 The anterior peduncles, therefore, are composed of (1) intra- 

 ciliary fibres (the majority of fibres composing them) ; (2) extra- 

 ciliary fibres ; (3) fibres from the hemispheres. The last two of 

 these are only present in small quantity. 



The rcstiform bodies have their origin, to a great extent, in 

 the fleece, and, therefore, consist chiefly of extra-ciliary fibres. 

 Those fibres, however, which pass through the central portion 

 of the restiform bodies, and which originate mainly in the spinal 

 cord, pass, in part, directly to the dorsal cortex of the vermis, 

 and in part pass around the corpus dentatum from without in- 

 ward, and extend over to the ventral portion of the vermis, 



