9C THE MEMBRANOUS LABYRINTH, BY PROF. RUDINGER. 



circular canals, the existence of which has up to the present 

 time been doubted. 



In the sacculi the fibrous layer is thin, except where the 

 nerves penetrate the osseous wall. At these points the sacculi 

 are not very intimately connected with the osseous wall (the 

 utriculus, however, more closely than the sacculus rotundus), 

 but are separated from it by a wide-meshed connective tissue 

 enclosing vessels and nerves. 



Fig. 303. 



Fig. 303. Fibrous network adjoining the vessels of the semicircular 

 canals of Man, with its cells. 



The second layer, the vitreous-like tunica propria, likewise 

 varies in thickness. At the attached parts of the membranous 

 canals it appears in transverse sections as a very thin layer, 

 which increases in thickness towards the free portion of the 

 wall, and acquires considerable dimensions at the points of 

 attachment of the ligaments of the labyrinth. In fresh speci- 

 mens it forms a hyaline substance that appears sharply de- 

 fined both externally towards the fibrous layer, and internally 

 towards the papillae. After the application of colouring agents 



