THE EAR. 411 



dunculated cells (s, s, s), one above the other, the undermost 

 being the longest, which may be termed " teeth of the third 

 series," (" cylinder epithelium-cells," Corti). The habenula 

 denticulata, as far as to the " teeth of the second series," is 

 covered by round or oval epithelium cells (h) which also occupy 

 the spiral sulcus below the " teeth of the first series," though 

 lying free and separate in immediate contiguity, and forming 

 a continuous layer only on the hamulus membranaceus. Upon 

 these cells and over the entire habenula denticulata, we then 

 find a peculiar, thin, finely striated membrane {l-v), which 

 externally projects a little over the commencement of the zona 

 pectinata, though separated from it by some large epithelial 

 cells (u), and passing internally upon the habenula sulcata, 

 where it is gradually thinned and ultimately lost. This mem- 

 brane, covered by the epithelium of the cochlear canal, can 

 hardly be viewed as anything but a continuation of the habe- 

 nula sulcata, and may be most suitably compared with the 

 zona pectinata. 



2. The zona pectinata (Todd and Bowman) (w'-w), is the 

 outer portion of the membranous spiral lamina, smooth on 

 both the upper and under surfaces, and affixed, at the outer 

 side, on a projection of the external wall of the cochlear canal. 

 It is a perfectly homogeneous lamella, but, except at the 

 borders, appears to be very closely ribbed, and thence assumes a 

 fibrous aspect. At its outer edge this lamina, which seems to 

 be opened out in a narrow border, receives a peculiar fibrous 

 substance (a?) arising from the wall of the cochlea, which there 

 presents a minute osseous ridge (the lamina spiralis accessoria), 

 Huschke; which Todd and Bowman describe as a cochlear 

 muscle, but in which I can perceive nothing but a form of 

 nucleated connective tissue, whence I shall term it the liga- 

 mentum spirale. 



The nei^ves of the cochlea enter the cavities of the osseous 

 zone from the canal of the modiolus, and there form a close 

 plexus of dark-bordered fibres, O0015"' in diameter, through- 

 out its whole length, and which, as discovered by Corti, con- 

 tains, at a very definite spot not far from the border of the zone, 

 an aggregation, at first, O'l"' in width, of bipolar, oval, minute, 

 (0011— 0016'" long, 00066— 0-0097/" broad), and pale gang- 

 lion-cells, which it is very probable intercept all the fibres of the 



