300 



ANATOMY OF THE CENTEAL NEEVOUS SYSTEM. 



strated that in it we have a segment of the sensory tract. Embryology and com- 

 parative anatomy equally substantiate this position. Later we shall trace the farther 

 course of the fillet. 



Thus the stratum lemnisci contains two elements: mesially the upper 

 and laterally the lower lemniscus. The lower lemniscus (better called lem- 

 niscus of the midbrain) arises chiefly from a system of fibers not yet men- 

 tioned: viz, the deep marrow, or deep medullary stratum of the midbrain- 

 roof ; the remainder arises from the ganglion of the corpus quadrigeminum 



-"X' 



cr^<t<' 



Fig. 193. — Diagrammatic horizontal section through the decussation of the 

 superior cerebellar peduncles and vicinity. The bundle to the optic tract is 

 questionable. Dirrkte Fasern ztiin Thalainvs. Direct fibers to the thalamus. 

 Hanbcnstrakhiiig, Tegmental radiation. Rothri- Kern, Tegmental nucleus. Re- 

 (jirm dcr Virhiigel, Region of the corpora quadrigemina. Bindeariit, Anterior or 

 superior cerebellar peduncle. 



posteritis. On an oblique frontal section through both pairs of quadri- 

 geminal bodies this is clearly shown (see Fig. 19-1). 



The ganglion in question consists of a large, round nucleus filled with 

 a net-work of fine fibers. As the ganglion of the posterior quadrigeminal 



