2/0 Journal of Comparative Neurology. 



common origin phylogenetically. And when the r. hyoideus 

 of Anura is compared with that of fishes there can be httle 

 gro.und for denying their equivalence. From this point of view 

 the r. jugularis must be morphologically a branchial nerve and 

 essentially post-trematic. 



The innervation of the m. cerato-hyoideus externus should 

 be noticed also in connection with the r. jugularis. The varia- 

 tion in the innervation of this muscle within the Urodela is re- 

 markable unless there have been numerous errors in observa- 

 tion. In Amblystoma the muscle is innervated by the r. jugu- 

 laris VII, though Fischer states that it gets fibers also from 

 the t. glossopharyngeus ; in Cryptobranchus japonicus (Hoff- 

 mann) by the r. jugularis and glossopharyngeus ; in Crypto- 

 branchus alleghaniensis, by the glossopharyngeus ; in Salaman- 

 dra according to Hoffmann by the r. jugularis and glosso- 

 phar)'ngeus, according to Druner by the r. jugularis and r. 

 communicans ; in Triton, Menobranchus and Proteus by the r, 

 jugularis and r. communicans (DruNEr) ; in Siren according to 

 Hoffmann by the glossopharyngeus, according to Wilder by 

 the glossopharyngeus and posterior palatine ; in Amphiuma 

 (Hoffmann) by the glossopharyngeus ; in Spelerpes by the 

 glossopharyngeus (Bowers). 



A study of these observations will show that in all cases 

 where the glossopharyngeus is reported to take part in the in- 

 nervation of the m. cerato-hyoideus externus, the methods of 

 investigation were largely or wholly dissection, excepting in the 

 investigations by Druner and Bowers. And in no case does 

 DruNER describe fibers from the glossopharyngeus to this 

 muscle excepting through the r. communicans, which he erro- 

 neously interprets as motor. Now, the t. glossopharyngeus 

 passes between the m. cerato-hyoideus at or near its insertion 

 and the branchial cartilage in a manner which might lead a dis- 

 sector to believe that it gives fibers to this muscle, but serial 

 sections show that, in every case of my observation, the nerve 

 passes through this relation intact. DrCner, also, notices this 

 fact in the Urodela which he studied. But for Bowers' obser- 

 vation upon Spelerpes, the above facts would lead one to think 



