AUDITORY OR HAIR-CELLS OF THE EAR. 465 



PLATE XXII. 



Fig. 18. .Shows the character of the radial fibres between the ganglion and 

 organ of Corti and illustrates the manner in which they may become for a greater 

 or less distance spiral in course. Htnk. oIdj. 2, Obh. cam. 



Fig. 19. A portion of the nerve plate from the lamina of a 10 cm. foetal ox to 

 illustrate the mixing or anastomosing of the fibres of the nerve bundles between 

 the ganglion and organ of Corti. Htnk. obj. 4, Obh. cam. 



Fig. 20. Two end brushes of nerve fibres ending in the Sauropsid organ. The 

 points of importance are the large varicosities (group of sheath cells) which the 

 fibres possess just before breaking up into the terminal branches, Htnk. obj. 5, 

 Obh. cam. 



Fig. 21. Three supporting cells from the Sauropsid organ and two nerve 

 fibres, which as stained, show in the one case an oval terminal body brown in 

 color, and in the other case only a free end. Htnk. obj. 5, Obh. cam. 



Fig. 22. Part of the nerve plate between ganglion and organ of Corti to show 

 branching fibres. Fibre 3 has a varicosity from which is given off a collateral 31 

 which in turn gives off one of its own 3" while the main trunk of 3 is continued 

 to the hair-cell at 3. The collateral given off from 31 divides into three terminal 

 branches or more correctly it gives off two other collaterals 31" 3'v while it is 

 continued to a hair cell not shown in the preparation. Fibre 2 under goes one 

 divison as does fibre i. Htnk. obj. 4, Obh. cam. 



Fig. 23. A single radial nerve fibre which from a triangular enlargement gives 

 off two processes one of which divides into two. These three processes extend to 

 the peripheral organ. Htnk. obj. 5, Obh. cam. 



Fig. 24. A surface view of the organ of Corti showing one row of inner hair- 

 cells and five rows of outer hair-cells. The fifth row is not continuous, but suffers 

 frequent interruptions. Htnk. obj. 4, Obh. cam. 



Fig. 25. Surface view of a part of the network of nerve fibres in the Cortian 

 organ at the base of the hair-cells. / the fibre which proceeds to the ganglion. 



Fig. 26. A view from above of the upper surface of the Cortian organ the 

 focus being on the arch of Corti. One outer hair-cell is stained and is connected 

 with an inner hair-cell, equally well stained, l:)y a nerve fibre which crosses the 

 Cortian tunnel somewhat obliquely. Owing to the point of view the nerve appears 

 to pass through the inner hair-cell, whereas it passes below it. Htnk. obj. 5, Obh. 

 cam. 



Fig. 27. Part of two commissures or connecting nerves lying just below, i. e., 

 in contact with the bases of the hair-cells of two inner rows of the outer series, 

 showing the characteristic enlargements and the numerous delicate processes 

 which are given off sometimes from the fibres, sometimes from the swellings. 

 At X is shown the bundle of fibres lying below the inner row of hair-cells, which 

 forms the most pronounced bundle of the so-called spiral nerves. A part of this 

 structure is shown more highly magnified in the next figure. Htnk. obj. 5, 

 Obh. cam. 



Fig. 28. The bundle of nerve fibres associated with the inner hair-cells to 

 show the nature of the fibres, which are extremely fine filaments. Leitz, obj. 12, 

 Obh. cam. 



