THE SENSE OF HEARING. 



; 57 



the basilar membrane and axis-cylinder of the terminal cochlear 

 branches of the auditory nerve. 



3. A Granular Layer composed of rounded cells. 



4. Cells in the sulcus spiralis which are cubical in shape. 



5. The External Auditory Cells, whose structure and arrange- 

 ment are very similar to the internal cells just mentioned. 



6. The Cells of Deiters, Hensen, and Claudius, which make a 

 prominence upon the interior of the cochlear canal. 



Fig. 313. Section of the Ductus Cochlearis and the Organ of Corti. 

 (After LANDOIS.) 



N, Cochlear nerve. K, Inner, and P, outer, hair-cells, n, Nerve-fibrils 

 terminating in P. a, a, Supporting cells, d, Cells in the sulcus spiralis. z, 

 Inner rod of Corti. 3/6, Corti, membrane of Corti, or the membrana tectoria. 

 o, The membrana reticularis. H, G, Cells filling up the space near the outer 

 wall. 



7. Reticular Membrane. The membrana reticularis is formed 

 by the superior extremity of the cells of Deiters. It possesses lacunae 

 which allow the passage of cilia of the cells. 



8. The Membrane of Corti, or membrana tectoria, is a soft, thick 

 membrane which covers the spiral groove and organ of Corti. Be- 

 neath it adheres to the cilia of the auditory cells. 



Auditory Nerve. The auditory nerve consists of two parts: the 

 cochlear, the hearing part, and the vestibular, the tonus part. The 

 cochlear part arises in the spiral ganglion of the cochlea, and', like a 

 >sterior root ganglion, sends a branch to the auditory cells in the 



