Kappers, Teleostean and Selachian Bram. /I 



this level there terminates the first decussated part of the tr. 

 tecto-bulbaris which runs from the com. ansulata along the raphe 

 and which Johnston, who found almost the same relations in the 

 sturgeon, calls tr. bulbo-tectalis. Only a small part of the more 

 lateral undecussated fibers of this tract run farther backward 

 (Figs, xcvii to xcix), turning gradually ventrad so that the two 

 groups of each side are very near each other and are separated 

 from the gray mass by the fibrae arcuatae externae, w^hose origin I 

 shall take up later. These bundles are the only ones of the tectal 

 fibers which continue farther caudad than the regio acustico- 

 facialis, reaching even beyond the regio glossopharyngeo-vagalis. 

 I am of exactly the same opinion as Haller regarding the ter- 

 mination of the main mass of tectal fibers in the regio acustico- 

 facialis. Haller, however, upon the examination of Golgi 

 preparations considered this region related with the motor nuclei, 

 though he does not positively say so. I am of the other opinion 

 that this region is connected with the area of the sensory nucleus 

 by the ventro-dorsal arcuate fibers which are here so numerous. 

 For this region I consider the tectal fibers as tertiary sensory 

 tracts from the nuclei of the oblongata. 



The third group of fibers which can be followed from the mid- 

 brain into the oblongata is the fasciculus longitudinalis posterior 

 or dorsahs. The situation of this tract, which is constant in all 

 animals, is the same m the mid-brain, immediately under the 

 aqueduct close to the raphe, in the oblongata and still farther back. 

 While I can recommend the summary which Van Gehuchten 

 gives of all that has been said about this tract in the higher verte- 

 brates and also Edinger's "Vorlesungen," yet I wish to point out 

 here what is known of this bundle in fishes. 



All investigators state that its fibers increase greatly in the 

 region of the nuclei of the oculomotorius and trochlearis and 

 GoRONOWiTSCH, JOHNSTON, Edinger, Haller and Van 

 Gehuchten are all of one opinion that it also receives fibers from 

 the motor nuclei of the oblongata. The statements about the 

 other relations of the fasciculus dorsalis, which are certainly not 

 less developed or of inferior interest, are far less numerous. 

 GoRONOwiTSCH observes in his work on Acipenser, "a part of 

 these fibers come from the valvula cerebelli, " and Johnston 

 describes as passing into the most anterior part of the cerebellum 

 "fibers — heavily medullated — emerging from among those of the 



