290 Journal of Comparative Neurology. 



tails, with Cole's description. Arising in two rootlets from the 

 first (most cephalic) root from the lobus vagi (sensory IX + 

 first sensory vagus root), it runs internal to the roots of the r. 

 lateralis vagi and the VIII nerve, then near the apparent origin 

 of the former nerve divides, one moiety running dorsad, inter- 

 nal to the r. lateralis X, the other external to it. On each of 

 these portions there is a ganglion, the two ganglia being distinct 

 and on opposite sides of the lateral line root. The nerves aris 

 ing from these ganglia merge dorsally of the lateral line root- 

 and continue dorsad and cephalad as the vagal root of the r. 

 lateralis accessorius, running up along the outer face of the 

 cerebellum intra-cranially to join the facial root, as already 

 described. 



The vagal root of the r. lateralis accessorius clearly arises 

 mainly from the common IX + X root, as just described, i. e., 

 is composed of communis fibers. It runs out, however, so 

 close to the intra-cranial jugular ganglion that it is impossible to 

 be sure that it does not carry out with it some general cuta- 

 neous fibers from this source. This may account for the scat- 

 tered medium sized fibers observed in this root, though I think 

 it more probable that these come from the r. lateralis vagi, 

 with which this accessory lateralis root is still more intimately 

 united. In this case these fibers, like the similar lateralis fibers 

 found in the facial root, doubtless distribute to pit-organs of the 

 top of the head. 



Upon emergence from the cranium, the r. lateralis acces- 

 sorius turns directly caudad, gradually becoming separated 

 from the cranium by the dorsal musculature. Having reached 

 the region of the supra-temporal canal, this nerve lies close 

 under the canal at its dorsal end. It has meanwhile given off 

 a number of small branches, composed chiefly of fine fibers, 

 but with some of medium size. Some of these run cephalad 

 from the foramen, some caudad. Their minute ramifications 

 spread out under the skin. None of these branches could be 

 traced to specialized sense organs, though this negative evidence 

 is of little value, as the skin here is not well preserved in my 

 specimens. 



