Stowell.] 1^8 [July 15, 



the same distance, still peripherad, an anastomotic filament from N. sympa- 

 thicus (Fig. 5, 6'). ' 



N. pliaryng'eus, the pharj-ngeal branch, takes its superficial origin 

 from the ventro-ental surface of N. vagus just caudad of the united trunks 

 of NN. vagus and accessorius, 7 mm. caudad of G.jugulare and entad 

 of the point where N. hypoglossus (XII) lies ectad of N. vagus ; its origin 

 is, therefore, involved in Px. gangliformis. A considerable accession is 

 traceable through the plexus to the accessory branch of N. accessorius. 

 Its course is ventrad, parallel with N. glosso-pharyngeus (IX), and only 

 2-3 mm. caudad of that nerve ; it lies ectad of A. carotidea interna, and 

 entad of V. jugularis interna and A. carotidea externa ; just peripherad of 

 its origin it gives a twig caudad to the trunk, which may be traced to G. 

 inferius (Fig. 5, 23). Opposite A. carotidea interna it divides into two 

 rami (Fig. 5, i22, a, b), from which filaments are given to A. carotidea 

 interna and to the adjacent V. jugularis interna. .From the cephalic 

 rmmis anastomotic filaments join N. glosso-pharyngeus (IX) to form a 

 plexus, from which filaments are distributed to the cephalic border of 

 MM. pharyngis constrictor medius, and pharyngis constrictor superior ; 

 others anastomose with filaments of N. sympatliicus and form the pha- 

 rj^ngeal plexus (Fig. 5), other filaments join N. hypoglossus (XII) in this 

 plexus. The caudal ramwshas its general course caudad ; 5 mm. peripherad 

 of its origin, it subdivides into two ramuli, which may be designated, in 

 view of their distribution, as the pharyngeal (Fig. 5-;?^), and the oesopha- 

 geal (Fig. 5, 25) ; the pharyngeal ramulus is directed meso-dorsad and 

 forms a loose network with the terminal filaments of tlie pharyngeal 

 ramuli of N. glosso-pharyngeus (IX) — Px. pharyngeus. The cesophar/eal 

 ramulus gives filaments to MM. pharyngis constrictor medius and pha- 

 ryngis constrictor inferior. 10-12 mm. caudad of the filaments to the mus- 

 cles of the pharj'nx a considerable twig joins the cephalic ramus of N. 

 laryngeus superior and receives an anastomotic filament from the caudal 

 ramus of the same nerve. The oesophageal ramulus continues along the 

 dorsum of the oesophagus caudad as far as the caudal third of the cervical 

 portion, interlacing in the plexus around that viscus.* 



N. laryng'eus supefior, the superior laryngeal branch, is consider- 

 ably larger than N. pharyngeus ; it takes its superficial origin from the 

 ventral border of the middle region of G. inferius ; its course is imme- 

 diately ventrad — occasionally it is directed caudad apposed to the main 

 trunk and ectad ot N. sympatliicus, 8-10 mm., at which point it turns 

 ventrad — and passes entad of A. carotidea primitiva, where it bifurcates 

 into a cephalic, ental, ramus, N. laryngeus infernus (Fig: 5, 7, ^.S") and 

 a caudal, ectal, ramus, N. laryngevs externiis (Fig. 7, 29). 



N. laryngeus internus is much larger than N. laryngeus externus ; 

 it accompanies A. laryngea superior, and with the artery perforates the 

 hyo-thyroid membrane at the ventro-caudal border of the cephalic cornu 



* It sometimes occurs that the caudal ramus is detached caudad ot the cephalic 

 ramus of N. pharyngeus ; In this case It constitutes usecoud pharyngeal nerve ; 

 this arrangement does not change its distribution. 



