244 Journal of Comparative Neurology. 



this position it turns ventrad and cephalad into the fourth bran- 

 chial arch, ventrally^ of the bar. It ultimately ascends along 

 the lateral side of the bar to the epithelium of the dorsal sur- 

 face. This terminal branch of the nerve corresponds to the 

 first intrabranchial divisions of the first {X, ibr. S) and second 

 {X, 2br. f) branchial trunks of the vagus. 



The ramus lateralis inferior arises as a terminal branch of 

 the t. visceralis. It turns ventrad along the lateral aspect of 

 the pharynx posteriorly of the remainder of the trunk, and in- 

 clines slightly cephalad in close relation with the r. recurrens X. 

 It then turns caudad and passes across the ental aspect of the 

 coracoid plate at the level of the glenoid fossa. From this 

 position it sends a twig mesiad which penetrates the pectoralis 

 muscle and innervates a small group of lateral line organs of 

 the pectoral region. The remainder of the ramus may pene- 

 trate the pectoralis muscle, or it may pass posteriorly of this 

 muscle to innervate the line of sense organs running caudad 

 from the axilla. 



In some cases the r. lateralis inferior assumes intricate rela- 

 tions with the branchial nerves in the axillary region, but in 

 other cases it is entirely removed from these nerves, so that 

 there is no possibility of its having a motor function. 



As the t. visceralis turns ventrad across the pharynx, it 

 gives off, also, the r. intestinalis {int.\ This nerve continues 

 caudad and forms into three divisions. One of these divisions 

 follows the lateral wall of the trachea to the lung. The other 

 two are distributed to the oesophagus. A few of the fibers of 

 the r. intestinalis are thinly medullated, but by far the greater 

 part of the nerve is made up of fibers which appear non-medul- 

 lated in Weigert preparations. It is impossible to say to 

 which of the vagus roots the neurones of the r. intestinalis be- 

 long. However, since the communis neurones of the second 

 vagus root have to do, largely if not wholly, with the branchial 

 trunks, it seem probable that those of the r. intestinalis belong 

 to the third vagus root. 



Beyond the origin of the r. intestinalis, the t. visceralis 

 becomes the r. recurrens {rec. X.'). It passes cephalad in the 



