202 Journal of Comparative Neurology. 



the latter. It sends branches to the cheek behind the angle of 

 the mouth and to the upper lip. Farther forward the main 

 trunk lies immediately above the maxillary bone and breaks up 

 into many fine branches behind the external nares. It is es- 

 pecially noteworthy that this ramus does not communicate with 

 the r. palatinus of the facialis, as in most other vertebrates. 



As noted above in connection with the origin of the sev- 

 enth nerve, the ramus fronto-maxillaris in Salamandra has its 

 own ganglion (the accessory ganglion of von Plessen and Rabin- 

 ovicz) which is quite distinct from the Gasserian ganglion. It 

 also derives its fibres from a dorsal root having the same posi- 

 tion and the same relation to the facial as our dorsal root (d). 

 Strong regards this dorsal root in Amblystoma as wholly facial. 

 That can hardly be in the case of Salamandra for the ventral or 

 maxillary ramus from this root effects the usual connection with 

 the ramus palatinus. It probably therefore contains at least a 

 large proportion of trigeminal fibres. In Amblystoma, on the 

 other hand, we have seen that the r. maxillaris does not effect 

 such connection with the r. palatinus and its homologies may 

 be regarded as less definitely fixed by its peripheral relations. 

 Yet from the comparison with Salamandra it would seem more 

 probable that the dorsal root in Amblystoma also sends its fibres 

 into the ramus fronto-maxillaris and that the latter should be re- 

 garded as largely, if not wholly, trigeminal. It is to be regret- 

 ted that an unfortunate accident has rendered impossible the defi- 

 nite determination of the exact courses of these fibres through 

 their ganglion in the specimens now under investigation. The 

 homologies as expressed above and as indicated on the plates 

 are therefore based mainly on peripheral distribution and may 

 require revision as our knowledge of the central connections of 

 the individual rami is extended. 



The ramus ophthalmicus (oflh.) is the largest of the branches 

 of the fifth nerve. From its peripheral relations it would seem 

 to have absorbed many fibres which are usually distributed with 

 other rami. It passes out of the Gasserian ganglion in company 

 with the sixth nerve and contributes some fibres to the latter for 

 the m. retractor bulbi, as previously described. Farther for- 



