550 'Journal of Co^nparative Neurology and Psychology. 



cutaneous branch he possibly mistook it for a motor branch. 

 KiNGSLEY describes and figures a branch of the first branchial 

 nerve as innervating the posterior portion of the depressor mandi- 

 bulae muscle. Such a relation would certainly be anomalous. 

 I do not find such a nerve, but in one specimen I find that the 

 ramus posttrematicus just as it begins to descend along the outer 

 anterior border of the first branchial arch divides into a posterior 

 portion that runs nearly in the usual course, and an anterior por- 

 tion that becomes almost lost among the fibers of the depressor 

 mandibulae muscle, rejoining the other division more ventrally. 

 This anterior portion, or possibly a still more aberrant but corre- 

 sponding branch, may be the one mistaken by Kingsley for a 

 division to the muscle. Ventrally the posttrematicus divides into 

 motor branches to the ceratohyoideus internus muscle and com- 

 munis branches to the lateral pharyngeal wall between the hyoid 

 and first branchial arches, the extreme anterior portion being the 

 ramus lingualis of communis fibers to the tongue. 



e. The second and third branchial nerves. — The second and 

 third branchial nerves [X.i. and X.2.) sometimes leave the gan- 

 glion as a common trunk that soon divides; sometimes they origi- 

 nate separately, but close together. They have the same general 

 arrangement of parts. They send branches to mm. levatores 

 arcuum branchialium 2 et 3 respectively. Each divides into a 

 ramus posttrematicus and a ramus pharyngeus. From the latter 

 ramus in each there runs anteriorly a small branch just dorsal to 

 the extreme dorso-lateral angle of the pharynx as far as the preced- 

 ing branchial arch and thence along the inner border of the latter, 

 supplying the ventro-lateral w^all of the pharynx. This answers 

 to a pretrematic ramus in its distribution. Druner's failure to 

 find a distinct pretrematic branch on either of these two nerves 

 is probably due to the fact that in adults, such as he examined, 

 it has become much attenuated. The main portion of the r. phar- 

 yngeus is distributed to the dorsal wall of the pharynx. The r. 

 posttrematicus after giving off a branch or branches to its corre- 

 sponding m. levator arcus branchialis turns ventrally and send- 

 ing off one or two small general cutaneous branches to the skin, 

 passes antero-ventrally along the outer border of its respective 

 branchial arch. 



The second branchial posttrematic sends branches to mm. 

 subarcuales recti i, 2 et 3 (m. constrictor arcuum branchiarum 



