4o6 Journal of Comparative Neurology. 



and passes through two foramena in the mesethmoid bone to 

 the sub-cutaneous tissue of the top of the head, supplying skin 

 and terminal buds. Its distribution area is altogether in front 

 of the eye and laterally of the nasal sac. 



After giving off its third branch, the main nerve rises up 

 nearly parallel with it to the dorso-lateral angle of the supra- 

 orbital cartilage and immediately passes through a foramen in 

 this cartilage and the overlying bone to run under the skin on 

 the dorsal wall of the cranium ventrally and laterally of the r. 

 ophthalmicus superficialis VII. At this level (dorsally of the 

 olfactory bulbs) the nerve give? off several small twigs for the 

 skin and terminal buds of the top of the head in the vicinity of 

 the posterior nasal aperture and then divides into four branches, 

 three of sub-equal size and one much smaller. One of the 

 larger ones, which may be regarded as the main nerve, follows 

 closely the r. ophthalmicus superficialis VII. The other three 

 turn laterally, following the inner wall of the nasal sac, and 

 then all enter the nasal barblet. 



The main nerve accompanies the facial ramus of the same 

 name along the inner border of the nasal sac, giving off numerous 

 small branches to the skin and its terminal buds, which are very 

 numerous throughout this whole region. Breaking up into num- 

 erous branchlets, it supplies the skin and terminal buds dorsally 

 and mesially of the nasal sac and forward to the tip of the snout — 

 the same region which receives the branches of the r. ophthal- 

 micus superficialis VII for pit organs. The termini of these 

 two ophthalmic nerves interlace freely, but anastomosis occurs 

 but rarely and even then is merely accidental and temporary 

 juxtaposition of the two kinds of fibers of no special morpho- 

 logical significance. 



To recapitulate, the ophthalmicus superficialis trigemini 

 arises from the ganglionic complex slightly cephalad and ven- 

 trad of the ophthalmicus superficialis facialis, emerges through 

 the cranium by a separate toramen, and pursues an entirely 

 separate course peripherally, lying ventrally of the latter nerve 

 and widely separated from it by the fleshy origin of the m. 

 dilator operculi. In front of the orbit it passes through 



