328 ELEMENTS OF HISTOLOGY. [Chap. xu. 



the outer wall i.e., the ligamentum spirale accesso- 

 rium caused by a small blood-vessel, the vas pro- 

 minens. 



473. Then we come to the stria vascularis, 



lining nearly the upper two-thirds of the outer 

 wall of the scala media. It consists of a layer of 

 columnar and spindle-shaped epithelial cells, between ' 

 which extend capillary blood-vessels from the ligamen- 

 tum spirale, and in some animals (guinea-pig) clumps 

 of pigment granules are found between them. 



474. Then we pass from the upper angle of the scala 

 on to the membrane of Reissner. This consists of a 

 homogeneous thin membrana propria, covered on its 

 outer vestibular surface with a layer of flattened 

 endothelium, and on its inner surface i.e., that facing 

 the scala media with a layer of less flattened, smaller, 

 polyhedral, epithelial cells. 



475. We come next to the vestibular labium of 

 the crista spiralis, on which peculiar cylindrical 

 horizontal projections anastomose with one another : 

 these are the auditory teeth (Huschke). The epi- 

 thelium of Reissner's membrane is continued as small 

 polyhedral cells into the grooves and pits between the 

 auditory teeth, but over the teeth as large, flattened, 

 squamous cells, which pass on, lining the sulcus 

 spiralis, and, as such, cover also the tympanic labium 

 of the crista spiralis. Now we arrive at the mem- 

 brana basilaris, on which the epithelium becomes 

 modified into the organ of Corti. 



476. The memforana basilaris consists of a 

 hyaline basement membrane, on which the organ of 

 Corti is fixed ; underneath this is i/lie tunica propria, 

 a continuation of the tissue of the ligamentum spirale, 

 composed of fine parallel stiff fibrils (Hannover, 

 Henle) stretched in a very regular and beautiful 

 manner in the direction from the ligamentum spirale 

 to the crista spiralis (Nuel). On the tympanic side 



