388 ANATOMY OF THE CENTRAL NBHVOUS SYSTEM. 



the posterior corpora quadrigemina. To these would be associated, also, 

 fibers arising in the nuclei situated in the lateral fillet just back of the cor- 

 pora quadrigemina (vide Pig. 206, b, outer side). The lateral fillet, therefore, 

 contains principally numerous neurons from the tertiary acusticus end- 

 stations. 



2. Kegarding the fossa rhomboidalis from above, one's attention is 

 drawn to several thick strands which, emerging out of the raphe, extend 

 laterally and lose themselves in the tissues close up to the cerebellum. 

 They do not all arise near together; it occurs rather often that one or 

 another of these bundles arises much farther forward in the floor of the 

 sinus, and extends backward in relatively long reaches, before it joins the 

 other bundles at the level of the acusticus. This striation is called the strics 

 acusticai; to the long, occasionally aberrant bundle in front Bergman has 

 applied the name conductor sonorus. 



While the first division of the cochlearis is connected with the fillet 

 through the medium of the corpus trapezoideum and the upper olive, it is 

 different with the part ending in the tubercle. This sends its strands direct 

 into the secondary acusticus tract, in the opposite fillet, and these fibers are, 

 in fact, the striae acusticje. 



Following their course more topographically, the striae arise out of the 

 tuberculum acusticum, situated between the pons and the cerebellum, and to 

 a smaller extent from the large cochlear nucleus (nucleus ventralis in the 

 figure), and then pass laterally around the corpus restiforme, just under the 

 ependyma of the ventricle toward the median line. Xear the raphe they dip 

 down deeper, and, while in the raphe itself, they turn anteriorly and cross 

 over to the opposite side, where they join the lateral fillet, considerably 

 augmenting its volume. 



Monakow saw atrophy of the strise after destruction of the opposite lateral 

 fillet high up near the corpora quadrigemina. Bumm and Baginsky observed them 

 degenerate toward tlie corpora quadrigemina after destruction of the cochlea. The 

 lateral fillet must^ therefore, contain fibers running in opposite directions. 



It will be seen that the point of greatest importance in this complicated 

 arrangement is that the nervus cochlearis, after once terminating in the 

 nucleus cochlearis and the tuberculum acusticum, has a higher tract going 

 to the posterior corpora quadrigemina. It runs by way of the lateral lem- 

 niscus. Still, only a portion of its fibers enters the lemniscus directly 

 through the stria''; a second very considerable portion passes first to the 

 oliva superior, traversing the trapezoid body, and thence arises the tract, 

 which enters the fillet and there joins the fibers from the strise acusticffi. 



The upper olives, interposed as they are in the central auditory nerve- 

 fibers, must be centers of importance. Their constant occurrence through 



