CoGHiLL, Cranial Ner^oes of Aniblystoma. 223 



p. V.) turns ventrad from its origin from the main nerve, then 

 a little laterad ventrally of the olfactory epithelium. It divides 

 near the transverse level of the posterior end of the internal 

 nares. The smaller twig arising from this division turns ab- 

 ruptly laterad posteriorly of the internal nares and anastomoses 

 with the lateral division of the r. palatinus VII (/. p.). As the 

 resulting nerve approaches the lateral border of the internal 

 nares it sends a small twig caudad while the rest of the nerve 

 turns cephalad and innervates the epithelium of the anterolateral 

 portion of the roof of the mouth. The larger division of the 

 ventral ophthalmic branch passes cephalad and soon anas- 

 tomoses with the mesial division of the r. ophthal-palatinus VII 

 imp.). This nerve passes along the mesial aspect of the internal 

 nares and becomes compressed between the vomerine bone and 

 the overlying cartilage. It sends fibers to the epithelium be- 

 tween the vomerine bone and the premaxillary. 



2. — The Truncus Infra-orbitalis . 



The infra-orbital trunk passes laterad from the Gasserian gang- 

 lion between the masseter and temporalis muscles to the lateral 

 border of the latter, then cephalad ventrally of the lateral part 

 of the eye. It contains lateralis neurones of the anterior division 

 of the lateralis VII root, and general cutaneous fibers from the 

 mesial part of the Gasserian ganglion. The point and extent of 

 fusion of these components are exceedingly variable. They 

 may fuse immediately upon leaving their ganglia, in which case 

 the general cutaneous component occupies an antero-ventral 

 position in the trunk; or they may not fuse until they turn 

 cephalad about the border of the temporalis muscle. In one 

 case I find the truncus mandibularis fused with the truncus 

 infra-orbitalis to near the lateral border of the temporalis 

 muscle, and this fusion is as complete as that at any point be- 

 tween the typical components of the trunk. 



Near the flexure of the infra-orbital nerve about the border 

 of the temporalis muscle it gives off a twig of fibres from both 

 components to the skin of the immediate vicinity. Other small 

 twigs, also, seem to be always given off in this region. As the 



