OLFACTORY KERVE. 



777 



and as they descend become very indistinct. The nerves of the outer wall 

 are divided into two groups the posterior branches being distributed over 

 the surface of the upper spongy bone, and the anterior branches descending 

 ever the plain surface of the ethmoid and the middle spongy bone. 



Fig. 530. 



XT I 



Fig. 536. NERVES OF THE SKPTUJI NASI, SEEN FROM THE RIOHT SIDE (from Sappey 

 after Hirscbfeld and Leveille). f 



I, the olfactory bulb ; 1, the olfactory nerves passing through the foramina of the 

 cribriform plate, and descending to be distributed on the septum ; 2, the internal or 

 septal twig of the nasal branch of the ophthalmic nerve ; 3, naso-palatine nerves. 



The olfactory nerves as they descend ramify and unite in a plexiform 

 manner, and the filaments join in brush-like and flattened tufts, which, 

 spreading out laterally and communicating freely with similar offsets on 



Fig.' 537. 



Fig. 537. NERVES OF THE OUTER WALLOP 

 THE NASAL FOSSJE (from Sappey after 

 Hirschfel.l and Leveille). 



1, network of the branches of the olfac- 

 tory nerve, descending upon the region of the 

 superior and middle turbinated bones ; 2, 

 external twig of the ethmoiclal branch of the 

 nasal nerve ; 3, spheno-palatine ganglion ; 

 4, ramification of the anterior palatine 

 nerves ; 5, posterior, and 6, middle divi- 

 sions of the palatine nerves ; 7, branch to 

 the region of the inferior turbinated bone ; 

 8, branch to the region of the superior and 

 middle turbinated bones ; 9, naso-palatine 

 branch to the septum cut short. 



each side, form a fine net-work 



with elongated and narrow intervals 



between the points of junction ; but 



it is impossible to trace by dissection 



the termination of the nerves in the 



membrane, in consequence of the difficulty of recognising the filaments, 



destitute of dark outline, as they lie among the other nucleated tissues. 



In their nature the olfactory filaments differ much from the fibres of the 

 cerebral and spinal nerves : they contain no white substance of Schwann, 



