222 Journal of Comparative Neurology. 



essentially constant in its peripheral relations, but the other 

 two show so wide variation that it is impossible to describe 

 any particular case as typical. 



The mesial terminal branch (in. o, p. V.) of the r. ophthal- 

 micus profundus passes cephalad mesially of the olfactory 

 epithelium near the dorsal roof of the nasal capsule. Within 

 the capsule the branch gives off numerous twigs which pass 

 dorsad to the skin. In one specimen seven of these twigs 

 penetrate the cartilaginous roof of the ear capsule by distinct 

 foramina. One of these comes in close contact with the r. 

 ophthalmicus superficialis VII but never anastomoses with 

 it. Another may anastomose with a division of the third 

 branch of the main nerve. In one specimen a large division of 

 the mesial branch passes laterad across the dorsal surface of the 

 olfactory epithelium and fuses with a division of the lateral ter- 

 minal branch of the main nerve. The resulting nerve goes to 

 the skin laterally of the external nares. 



Within the nasal capsule the mesial branch comes in con- 

 tact with a large branch of the olfactory nerve and remains 

 closely compressed against its surface for some distance, but 

 there is no interchange of fibers between the two nerves. The 

 differential myelin stain by the side of the non-medullated fibers 

 of the olfactory nerve makes this relation perfectly clear. 



The distribution, then, of the mesial terminal branch of 

 the ophthalmicus profundus is to the skin over the anterior part 

 of the nasal capsule anteriorly to the tip of the snout and lip, 

 and from the mid-dorsal line to some distance laterally of the 

 external nares. 



The particular relation which the lateral terminal branch (/. 

 0, p. F.) of the ophthalmicus profundus may assume with the 

 mesial terminal branch has already been mentioned. It inner- 

 vates the skin of the snout and lip laterally and posteriorly of 

 that innervated by the mesial terminal branch, as far as the 

 anterior canthus of the eye. Its fibers frequently come in close 

 relation with the r. buccalis VII, but there is no anastomosis 

 between the two nerves. 



The ventral terminal btanch of the ophthalmic nerve {^. o. 



