450 AVERS. [Vol. VIII. 



mose with the processes from neighboring cells and thus form 

 a delicate plexus of fibres where the anastomoses are numerous, 

 PI. II, Figs. II and 17, PI. Ill, Figs. 25 and 27, will serve to 

 give a faint idea of the character of this plexus. In Fig. 27, 

 PI. Ill, the sub-epithelial commissure (c) is shown, while in 

 Fig. 25 there is depicted a few meshes of the plexus connected 

 with one of the commissural varicosities {v). From each of the 

 varicosities pass off two sorts of fibres. Those which form part 

 of the plexus, and those which serve to connect the hair-cell 

 with the varicosity. Of the former sort are the " spiral fibres " 

 which enter the plexus. Only a few of the spiral fibres are 

 thus engaged. 



B. The Radial Nej'ves. 



When the cochlea is viewed perpendicularly to its helical 

 axis, the greater number of the nerve fibres, leaving the organ 

 of Corti, run nearly at right angles to the tangent of their 

 point of origin into the cochlear ganglion, and thence toward 

 the helical axis, about which all the fibres are spirally twisted 

 as they descend to the base of the helix (PI. I, Fig. i). Some 

 of the fibres, between their hair cells and ganglion cells, 

 suffer displacement in the horizontal plane, which often nearly 

 doubles their length between these two points. 



Lateral displacement in this plane occurs in greatest abund- 

 ance in the organ of Corti (PI. I, Figs. 4 and 7 ; PI. II, Figs. 

 8, 13 and 17; PI. Ill, Figs. 18, 19, 22, 23, 27 and 31), next in 

 the region of the Lamina ossea, and least of all — though still 

 to a considerable degree within the cochlear ganglion itself, 

 where it gives rise to the appearance of bands of spiral fibres 

 (PI. I, Fig. 7s, and PI. II, Fig. 12, spiral fibre), much the same 

 as within the cochlear organ itself. The bundles in the 

 ganglion are larger than those of the organ of Corti, a char- 

 acter not shown in the figures where only a single fibre is 

 drawn in. 



When viewed at right angles to the vertical or helical axis 

 the nerve fibres form a series of incomplete funnels with the 

 hair-cells as their thickened borders. This appearance is due 

 to the fact that the fibres leave the organ of Corti in a nearly 



