NERVE SUPPLY OF PINEAL SYSTEM OF SPHENODON 259 



(1) The left pineal nerve commences in the nerve-fibre layer of the 

 retina, passes from the proximal pole of the eye through the space which 

 is enclosed by the outer fibrous capsule of the eye, being covered here 

 by a sheath continuous with the inner fibrous capsule (Figs. 183 and 184). 



Fig. 183. — Sagittal Section of the Pineal Eye of Sphenodon, showing the 

 Pineal Nerve, Lens, Vitreous Body, Accessory Cavity, Capsula Interna, 

 Capsula Externa, Parietal Plug, and Vessels including Branches of 

 the Longitudinal Sinus. (After Dendy.) 



A. Cav. : accessory cavity. /. ." lens. 



accessory cavity. 

 ce. : capsula externa. 

 ci. : capsula interna. 

 c. vit. : vitreous body. 



n.p.e. : pineal nerve. 



P.P. : pineal plug. 



si. : longitudinal sinus. 



It then passes into and through the dura mater, where it comes into relation 

 with branches of the anterior pineal artery. Here it divides into two 

 and then three branches and lies between two vessels formed by a loop 

 of the sinus longitudinalis. It lies above the paraphysis. Hitherto 

 the nerve has been approximately in the median plane just beneath the 

 dense connective tissue of the cranial wall and in the dura mater. It 

 now passes once more as a single strand to the left of the pineal artery, 

 and, having left the dura mater, it reaches the anterior extremity of the 

 pineal sac and passes beneath its ventral wall to the left of the median 



