156 EDWARD PHELPS ALLIS, JUN. 



position dorsal or dorso-lateral to that bar. The main nerve, 

 continuing forward, here breaks up into raauy branches, some 

 destined to supply the supra-orbital canal organs 17 to 34, as 

 ali'eady stated, certain others being general sensory ones, 

 but much the larger part of the nerve going to supply the 

 deep ophthalmic group of ampullae. 



Ramus Ophthalmicus Profundus. 



The ramus ophthalmicus profundus issues from the skull by 

 a special foramen, as already stated, the foramen lying some- 

 what posterior to, and nearly in line with, the foramen for the 

 nervus oculomotorius. As the nerve issues from its foramen 

 it lies immediately anterior to the surface of insertion of the 

 rectus inferior muscle, immediately dorsal to the ventral head, 

 or bundle, of the rectus internus, at or near its insertion, and 

 ventro-anterior to the rectus superior. Running forward and 

 slightly outward from there it passes dorsal to and then lateral 

 to the inferior branch of the oculomotorius, which latter 

 nerve here runs backward. The profundus here lies posterior 

 and ventral to that branch of the oculomotorius that inner- 

 vates the rectus superior muscle, and posterior to the point 

 of origin of the several branches to the rectus internus, thus 

 crossing the oculomotorius distal to those branches. The pro- 

 fundus thus here lies in its well-known position — between the 

 superior and inferior divisions of the oculomotorius, ventral 

 to the one and dorsal to the other. Running outward and 

 forward the nerve passes through the interval between the 

 two bundles of the rectus internus, already described, here 

 accompanying the inferior branch of the oculomotorius, but 

 running in the opposite direction to that nerve. While iu 

 this interval a branch arises from the lateral surface of the 

 profundus, and there is, at this point, a small group of gan- 

 glion cells which lie on the external surface of the profundus 

 and along the base of the branch in question. These cells 

 have the size and general appearance of the ganglion cells of 

 the cerebro- spinal ganglia, and not that of those of the ciliary 

 o-anglion. They would seem, accordingly, to represent a 



