STRUCTURE OF THE WALL OF THE LABYRINTH. 



101 



served in chromic acid. Whilst the great majority of the 

 processes of the connective-tissue corpuscles are circularly dis- 

 posed in the canal, others traverse the thick part of the canal 



Fig. 305. 



Fig. 305. Transverse section of the sagittal semicircular canal of 

 the Pigeon. 1, Osseous semicircular canal ; 2, thin portion of the 

 wall of the membranous canal coalesced with the periosteum ; 3, thick 

 portion of the wall, with a groove for an artery ; 4, epithelium of a 

 different character from the pavement epithelium ; 5, pavement epi- 

 thelium ; 6, plexiform trabeculse stretching between the periosteum 

 and the outer surface of the membranous semicircular canal. Mag- 

 nified 170 diameters. 



in a direction from without inwards. (See fig. 306.) The 

 coarse vascular networks that surround the membranous canal 

 also partially dip into the cartilage, without however extending 

 as far as the epithelial layer of cells. 



