ORGAN OF CORTI. 151 



cochlea, at least in Man. These connective-tissue fibres are ob- 

 viously the remains of the original mucous tissue of the scala. 



I am unable to determine whether the membrana basilaris 

 possesses an unusually high degree of elasticity ; it does not, 

 at any rate, exhibit a disposition to roll inwards at the edges ; 

 it tears easily, and successful transverse sections show that the 

 membrane is always smooth and tense between its two points 

 of attachment. 



The parts of the ductus cochlearis hitherto described must be 

 regarded as constituting its proper connective-tissue wall, or membrana 

 propria, under which term I include Reissner's membrane, the inner- 

 most layer of the lateral connective-tissue cushion with the stria vascu- 

 laris, and the ligamentuin spirale, the homogeneous layer of the 

 membrana basilaris, and the crista spiralis. An objection can only 

 be raised, perhaps, to the latter, and I may observe in regard to it, 

 that it is easy in the cochleae of Man, which have been long pre- 

 served in glycerine, to detach the crista, together with the mem- 

 brane of Reissner and the membrana basilaris, from the outer border 

 of the lamina spiralis ossea, and thus to show that it is an integral 

 part of the proper wall of the ductus. 



EPITHELIAL LINING OF THE DUCTUS COCHLEARIS. 

 ORGAN OF CORTI. 



We have already spoken of that part of the epithelium of 

 the cochlea which covers the crista spiralis, the membrane of 

 Reissner, and the outer wall of the ductus ; the most important 

 part, however, the epithelium of the membrana basilaris, still 

 remains to be carefully described. 



The middle part of the basilar stratum of epithelium forms 

 the organ of Corti of Kolliker (figs. 321, 322. fp; fig. 324, 

 III ; fig. 326), the several parts of which are formed of more or 

 less modified columnar epithelial cells and cuticular formations. 

 The organ of Corti, again, is itself (see the sections exhibited in 

 figs. 321 and 331) arranged with lateral symmetry around a 

 centre that at the same time forms a supporting framework 

 the arches of Corti. The arches overhang the membrana 

 basilaris, and are composed of an internal and of an external 

 pillar or rod. The row of internal hair cells (fig. 326, e, and 

 fig. 331, ij and the granule layer (fig. 331, h i), as well as more 



