98 AYERS. [Vol. VI. 



view that they formed an end apparatus for the perception of 

 pressure stimuli, in harmony with his view that the stiff hairs 

 of the hair cells were bumped against or into the membrana 

 tectoria, which rests upon them like a foreign body, by the 

 vibrations of the membrana basilaris. In the case of the inner 

 cell hairs they strike against the rows of knobs above described. 



Hensen formerly thought the membrana Cortii was very soft 

 and almost mucous in nature ; he now thinks it to possess a re- 

 sistance comparable to that of a pillow stuffed with feathers. 

 Its stickiness is due to the fibrous net on its dorsal surface 

 (Loewenberg's net), as well as to the fibrous nature of the mem- 

 brane itself. 



Gottstein (1872, 103) : In man the membrana Cortii begins 

 about the middle, between the attachment of the membrana 

 Reissneri and the labium vestibulare. Within from this line is 

 a continuous layer of epithel cells ; but no trace of a tectorial 

 membrane. The fibrous bodies of the pillars of Corti are com- 

 posed of fibres which run into the basilar membrane. Proto- 

 plasmic remains have been found around their upper ends, and 

 Waldeyer saw nuclei there in young animals. 



The membrane of Corti is divided into three zones, and ends 

 free in the neighborhood of the outermost hair cells. In the 

 little epithelial ridge of the embryo there arises a triangular 

 cell, which soon divides into two, in each of which a fibrous 

 body appears, the first traces of the pillars of Corti. 



The outer hair cells arise by the fusion (soldering) of two 

 cells, an upper and a lower. 



In animals the membrana tectoria begins near the line of 

 insertion of Reissner's membrane ; in man, further out (as above 

 stated). The innermost zone reaches from this line to the 

 labium vestibuli cristse spiralis, thin and structureless ; in man 

 it is relatively thicker. The middle zone is separated from the 

 first by a fine spiral line ; it extends to the inner hair cells, and 

 is especially thick and fibrous radially. The outer zone is 

 separated from the middle by a slender hyaline spiral seam, 

 and forms a fine-meshed network. The processes described by 

 Boettcher, connecting hair cells and membrana tectoria, and 

 the knobs on the lower surface of the membrana tectoria which 

 Hensen saw, Gottstein could not find. Gottstein did not agree 

 with Boettcher that the hairs occupy only a curved line on the 



