238 Journal of Comparative Neurology. 



As the t. glossopharyngeus turns cephalad into the first 

 branchial arch, it gives off a motor branch {IX, 7) to the first m. 

 depressor branchii; and beyond this the trunk is considered as 

 the r. post-trematicus IX {pst. IX). It contains motor and 

 communis fibers. It passes cephalad in a position lateral of the 

 ventral portion of the first epibranchial bar and crosses the dorsal 

 surface of the m. ceratohyoideus internus. It innervates this 

 muscle {IX, 8), and in the same region sends a twig {IX, ^) lat- 

 erally of the cartilage to the epithelium of the pharyngeal side 

 of the bar. The terminal ramus finally turns abruptly dorsad 

 anteriorl}' of the branchial cartilage to the dorsal side of the 

 hypohyal, and distributes itself to the epithelium overlying the 

 anterior part of the hyoid and branchial cartilages. 



2. — The First Tntncus BrancJiialis Vagi. 



The first t. branchialis vagi {X, ibr.) leaves the ganglion 

 of the IX+X a little posteriorly of the glossopharyngeus and 

 immediately in front of the second branchial trunk, or these 

 two trunks may arise together. The general course of the first 

 trunk is latero-caudad across the ventral side of the second m. 

 levator arcus branchii, then along the lateral surface of this 

 muscle to the distal end of the first epibranchial bar, caudally of 

 which it gives off three important branches, and beyond this 

 branching enters the second branchial arch. 



The r. pre-trematicus (/;'/. X,i) of this trunk arises a short 

 distance from the ganglion. It is of about the same size as the 

 r. pre-trematicus IX. It inclines slightly caudad to the dorsal 

 end of the first branchial cleft, in front of which it extends along 

 the dorsal border of the first epibranchial bar. As the nerve 

 enters the branchial arch, it receives the fifth ramus of the glos- 

 sopharyngeus, The resulting nerve is distributed to the epi- 

 thelium of the pharyngeal side of the distal portion of the bar. 



A pharyngeal ramus {X, I br.i) arising either Avith the r. 

 pre-trematicus or near it, passes cephalo-mesad ventrally of the 

 ganglion IX+X to the epithelium of the pharynx. From the 

 pharyngeal ramus there sometimes arises a third exceedingly 

 ■fine twig (not figured) which anastomoses with the r. pre-tre- 



