28o Journal of Comparative Neurology. 



internus is innervated in Proteus and Menobranchus (DrUner, 

 p. 451) wholly by the t. glossopharyngeus. In Salamandra 

 and Triton larvae, and also in Siredon, according to Druner, 

 this muscle receives fibers from the plexus subceratobranchiales, 

 a plexus which is formed by the fusion of the terminal ramuli 

 of the r. post-trematici. In Amblystoma larvae, however, I 

 have found no such plexus, and the m, cerato-hyoideus is inner- 

 vated by the t. glossopharyngeus alone. Drcner maintains, 

 also, that the t. glossopharyngeus participates in the innerva- 

 tion of the first m. levator branchii. I have not found such a 

 condition in any of my specimens. 



In Salamandra larvae, Drunek (p. 500) has described a 

 peculiar nerve which he calls "N. cutaneus retrocurrens IX." 

 This nerve arises from the t. glossopharyngeus, or the r. post- 

 trematicus IX, in the region of the m. cerato-hyoideus internus, 

 penetrates this muscle ventrad and later the m. interhyoideus 

 also. After passing through the latter muscle it inclines more 

 laterad subcutaneously and is distributed " zu einer Reihe von 

 knospenformigen Sinnesorganen. " 



This observation of a branchial nerve innervating cutane- 

 ous sense organs in Amphibia is unique. It is unfortunate 

 that Drlner has not given data by which the exact nature of 

 these organs may be known. A priori they would be inter- 

 preted as belonging to the cutaneous terminal bud system, since 

 no lateralis fibers are known to enter the t. glossopharyngeus 

 in Amphibia. But the terminal buds are supposed to occur in 

 the skin in fishes only. However, I have myself observed 

 organs in the skin of Amblystoma in the region of the gills 

 which have neither the typical appearance nor the typical inner- 

 vation of lateral line organs. I have observed, also, that com- 

 munis fibers probably go to the skin from the t. hyomandibu- 

 laris, yet I have been unable to demonstrate conclusively the 

 presence of terminal buds in the skin of Amblystoma. This 

 observation of DrCner's, however, makes it seem probable 

 that such organs do exist in the skin of some larval Amphibia. 



