CRANIAL NERVES OF CAECILIANS 539 



In the larva of Ichthyophis (fig. 35) the ninth nerve separates 

 from the vagal root just as their respective ganglia are reached. 

 From the ninth ganglion a small ramus pharyngeus {IX ph.) is 

 given off laterally, and from its posterior end a ramus posttre- 

 maticus (IXpst.) passes out. The sympathetic trunk is very 

 closely associated with the glossopharyngeal, but an anastomosis 

 was not with certainty detected. In the adult the relations are 

 much the same. 



S. The second branchial nerve 



/ Arising in common with the first branchial nerve (fig. 38, 

 IX + X), or more often from the trunk ganglion of the vagus, 

 in Herpele, is a nerve which runs posteriorly at the dorsal border 

 of the thyreoid gland, then, curving ventrally around the posterior 

 border of the same gland, turns anteriorly to run along the lateral 

 border of the second branchial cartilage, farther anteriorly 

 along the pharyngeal epithelium between the second and third 

 branchial arches, ramus posttrematicus X.l. Before curving 

 around the thyreoid it may give off a ramus pharyngeus to the 

 dorsal pharynx, or the latter may arise separately from the main 

 tenth trunk. From the main ramus, just as it is curving ante- 

 riorly, a posteriorly directed branch is given off, passing to the 

 lateral wall of the pharynx, possibly a remnant of a third bran- 

 chial nerve. The second branchial nerve is exclusively sensory 

 (fig. 44, X.lph., X.lpsL, X.lphp.). Both the first and second 

 branchial nerves in Herpele are in some parts much atrophied. 



In Dermophis, as seen in figure 36, the second branchial nerve 

 is not greatly different from the condition in Herpele. 



As mentioned in a previous section, the second branchial nerve 

 in Geotrypetes arises from the IX-X-sympathetic ganglion in 

 the form of a ramus pharyngeus (fig. 37, X.lph.). 



In the larva of Ichthyophis a second branchial nerve arises 

 from the dorsal border of the vagal trunk ganglion (fig. 35, 

 X.lpst). 



In Caecilia, as stated in a preceding section, the second bran- 

 chial nerve arises from the root ganglion of the vagus. 



