596 MEMBRANE OF CORTI. [sect. 234. 



or rather with the reticulated lamina, but I have now satisfied 

 myself that they pass through the foramina of the lamina reticu- 

 laris, and lead into small spindle-shaped cells lying beneath the 

 organ of Corti, between it and the membrana basilaris. These 

 cells are probably connected with the terminations of the auditory 

 nerve, of which more hereafter. 



B. The zona pectinata of Todd and Bowman (figs. 242, 243, 

 w'-ic) is the outer portion of the lamina spiralis membranacea, or 

 basilar membrane ; it is quite smooth on both its aspects, and is 

 fastened externally to a projection of the outer wall of the cochlear 

 canal. This is a perfectly homogeneous lamella which appears to 

 be closely ribbed (except at its borders) in the transverse direction 

 of the cochlear canal, and thus acquires a fibrous aspect. Exter- 

 nally, a narrow tract of this lamella appears perforated, and it is 

 here continued into a peculiar fibrous substance (fig. 241,/), which 

 springs from the walls of the cochlea along a minute osseous ridge, 

 the lamina spiralis accessoria of Huscke. This fibrous substance is 

 described by Todd and Bowman as the musculus cochlearis, but 

 as I find it nothing but a form of nucleated connective tissue, 1 

 prefer to designate it the ligamentum spirale. 



The membrane of Corti, which forms the opposite boundary of 

 the scala media (the basilar membrane limiting it on the other 

 side), is extremely difficult to see in its natural situation. Figure 

 241 is carefully drawn from the best transverse section of the 

 cochlea which I have been able to obtain) yet I will not venture 

 to maintain that it affords a correct representation in all its parts. 

 According to my inquiries up to the present time, the membrana 

 Cortii consists of a special striated lamella, an epithelium, and a 

 delicate stratum of ordinary connective tissue. The epithelium 

 and connective tissue seem to be prolongations of the lining of 

 the scala vestibuli, stretching between the ligamentum spirale on 

 the one hand, and the teeth of the first series and the osseous zone 

 on the other hand ; underneath this prolongation, and therefore 

 looking towards the scala media, is the striated lamella, which alone 

 constitutes the membrane seen and described by Corti. In spite 

 of the fact that this membrane may be isolated in every prepara- 

 tion with the greatest ease, still no observer has yet made out its 

 relations in a satisfactory w r ay : in figure 245, I therefore give a 

 transverse section of the membrana Cortii from the first turn of 

 the cochlea in the ox. Here it will be seen, that this structure is 

 very thick (up to vol!" , in a zone only o , o6' // broad) in about the 

 half of its breadth, while the other portion runs off into quite a 









