100 'Journal of Comparative Neurology and Psychology. 



The relations of the sensory radices are also very simple in Galeus 

 and Angelus squatina where we see their fibers spreading out like 

 a short pencil within the lobe, as already described by Rohon 

 in his study of the vagus. Ascending or descending root fibers 

 (the latter in higher vertebrates constituting the fasciculus soli- 

 tarius) are scarcely observable, and, if present, are extremely 

 short, as in the teleosts. From the tr. descendens nervi quinti I 

 did not see any fibers passing into the glossopharyngeus, as Kings- 

 bury records for some ganoids and teleosts. 



Between the vagus and the glossopharyngeus, and accordingly 

 somewhat farther caudad than in the teleosts, the so-called nervus 

 lateralis vagi enters the oblongata directly into the posterior con- 

 tinuation of the octavus field (Fig. cv). By reason of the great 

 decrease backward of the lateral sensory field the vagus roots enter 

 at a more dorsal level than those of the glossopharyngeus. The 

 motor fibers of the vagus termmate m the same way as those of the 

 ninth nerve and these decussating fibers before they enter their 

 nucleus under the floor of the ventricle form a separate bundle 

 immediately lateral to and belonging with the fasciculus dorsalis 

 (Figs, cv, cvi). 



The sensory fibers pursue the same course as those of the glosso- 

 pharyngeus. Here, also, we see little tracts of ascending and 

 descending fibers ending brush-like within the lobus. At about 

 this level of the oblongata there begins an important collection of 

 gray matter ventrally close to the septum, which reminds one of 

 the gray mass beginning farther cephalad in the teleosts. 

 Edinger indicates it in Scyllium and calls it nucleus paraseptahs. 

 It is rather difficult by my methods of investigation to give a com- 

 plete account of it. It may be the same as that described by 

 Johnston in the ganoids as the lower olive, the neurites of whose 

 cells this author says cross the ventral raphe and finally break up 

 among the lateral tracts. As Fig. cvii shows that in the selachians 

 this gray mass contains a great many fibers which take that course, 

 this seems the more probable because the nucleus paraseptalis 

 extends into the beginning of the cervical cord, where Johnston 

 found his lower olive. Haller thought that in the region of the 

 vagus some fibers of the fasciculi mediani of Stieda might end 

 or originate. I am able to contradict this for Galeus and I think 

 that Haller has considered decussating motor vagus fibers as 

 such (Fig. cvi). These fibers run to their nucleus across the 



