98 



THE MEMBRANOUS LABYRINTH, BY PROF. RUDINGER. 



that the tunica propria is here present, though certainly only 

 as a very thin layer (see fig. 302). Towards both sides the 

 processes begin to increase in size, and then become (as shown 

 in the figure) larger on the right and left hand ; again diminish- 

 ing in height at the free wall of the labyrinth. At this last- 

 named part they are frequently but little elevated above the 

 free surface, so that on examination with low powers they may 

 appear to be absent. Their internal surface is everywhere 

 covered, as well in the depressions between the papillae as on 



Pig. 304. 



v 



Fig. 304. Surface view of the papillae of the membranous horizon- 

 tal semicircular canal (stained with nitrate of silver solution). 1, 2, 

 3, papilliform structures, with their investing epithelium. 



their summits, by a single layer of tesselated epithelium, which 

 may be brought into view without much difficulty with vari- 

 ous agents, both in surface and profile views. But since these 

 epithelial cells become rather easily detached, and the smallest 

 papillae frequently only bear from three to five epithelial cells 

 (see fig. 304), the nuclei of the cells cannot always be seen in 

 profile, which has led to the existence of the epithelial cells on 

 the summit of the papillae being incorrectly denied (Lucge). 

 The epithelial cells on the papillae and neighbouring parts are 

 of irregular form, and by maceration in solution of nitrate of 

 silver their contours can be traced over all parts of the eleva- 

 tion. Inasmuch as these structures first make their appear- 

 ance after birth, it is probable that during their development 



