542 yoiirjial of Comparative Neurology and Psychology. 



i. The rajnus jugularis VII . — ^At about the level of the origin 

 of the r. mentalisinternus there is given off from the hyomandibular 

 trunk a small motor branch to the anterior division of the depressor 

 mandibulae muscle. Another motor branch to the same division 

 of the muscle runs along and in the anastomosis X ad VII. 

 At about the place where the hyomandibularis finally breaks up 

 into the larger divisions of the r. jugularis it is joined by the anas- 

 tomosis from the glossopharyngeal-vagal complex carrying general 

 cutaneous fibers. The origin and composition of this commissure 

 will be considered under the subject of the glossopharyngeus and 

 vagus nerves. The r. jugularis is distributed to the interhyoideus 

 (mylohyoideus posterior), depressor mandibulae (digastricus) and 

 sphincter colli (levator maxillae inferioris ascendens of Fischer, 

 quadrato-pectoralis of Druner) muscles, and in addition carries 

 general cutaneous fibers to the skin overlying these muscles. Lat- 

 eral line fibers also occur in the r. jugularis. 



k. The ramus lateralis VII. — -There is one branch of the r. 

 jugularis, if indeed it may be considered as a branch of the latter, 

 that requires especial mention. It was first described by Fischer 

 as a structure peculiar to Amphiuma, and said to be traced to the 

 hyotrachealis (interbranchiahs 4) muscle. Kingsley states that 

 it supplies the dorso-trachealis muscle. The writer (1904) gave 

 a brief description of this nerve, showing that it does not end in the 

 dorso-trachealis muscle, but passes posteriorly into the trunk 

 region as far as the pelvis. There was suggested a possible rela- 

 tion to the neuromasts of the trunk, and the nerve was provisionally 

 designated as r. laterahs VII. In the same year (1904) appeared 

 the paper of Druner in which he described the nerve, calling it 

 nervus lateralis VII and asserting that it supplied in part the 

 median series of neuromasts of the trunk, that is, he considered it 

 a lateral line nerve. In the following year the writer in a second 

 paper withheld the name, r. lateralis VII, believing that the 

 evidence of the presence in the nerve of lateral line fibers was not 

 convincing. The statements of Druner as to the composition of 

 the nerve may now be confirmed. It is composed largely, if not 

 entirely, of laterahs fibers; I have not, however, as yet detected 

 any connection between it and the neuromasts of the trunk. 

 Such connection doubtless exists. Most of its fibers come from 

 those branches of the r. jugularis that supply the posterior division 

 (cerato-mandibularis) of the depressor mandibulae muscle. In 



