71 



nerve of the corresponding side (fig. 70 Ant. Sup. oph.). 

 The most anterior of these pierces the cranial cartilage and 

 so enters the orbit, and runs for a short time along its 

 inner wall. Then, piercing the muscles of the eyeball, it 

 runs externa] to this out to the eyelid, where it ends in 

 several fine branches (fig. 74, ^4//^. Sup. oph.). The two 

 posterior nerves are motor only. Piercing the cranial 

 wall, and entering the orbit, they are distributed to the 

 dorsal region of the muscles of the eyeball. 



B. (I) The Posterior Superior Ophthalmic (fig. 74, 

 Post. Sup. oph.) is a rather stout nerve, arising from the 

 postero-dorsal angle of the visceral ganglion, anterior 

 to the pallia] nerve (fig. 70). Running outwards, this 

 nerve penetrates the cranial wall and so enters the orbit. 

 Were it runs internally to the wall of the orbit, and 

 external to the white body for a short time, and soon 

 expands into a small oval ganglion. Piercing the 

 muscular wall of the eyeball, it inns over its outer surface 

 (fig. 74, Post. Sup. oph.), and finally ends in several 

 branches which are distributed to the eyelid. 



P. (2) The Inferior Ophthalmic are three nerves 

 on each side, of which the posterior is the least and is 

 purely motor, being distributed to the inferior muscular 

 wall of the eyeball. All three nerves, arising from the 

 lateral face of the sub-oesophageal ganglionic mass, rather 

 in front of the median line, ran outwards and enter the 

 orbit after piercing the cranial wall. The anterior nerve, 

 after running for a time on the inner wall of the orbit, 

 pierces this, and then runs along its outer wall to the 

 eyelid, where it ends in several fine branches. The 

 median nerve of the three is the largest and lias a course 

 similar to that of the posterior superior nerve. Like this, 

 it bears a ganglion, but runs over the antero-inferior 

 surface of the eyeball (fig. 75, Inf. oph. N.). 



