NORMAL HISTOLOGY. 



388 



membranous structures. These vessels form a wide-meshed 

 capillary net-work within the fibrous tunic of the canals and the 

 ampullae, which supplies both the endo- and perilymphatic surfaces. 



THE COCHLEA. 



The cochlea consists of the tapering bony tube wound spirally 

 about its axis and containing the highly-specialized but much 

 smaller epithelial canal, the ductus cochlearis. This latter tube, 



FIG. 400. 



Longitudinal section of cochlea of guinea-pig : a, bony capsule ; b, central shaft 

 or modiolus ; c, lamina spiralis ; d, canal of modiolus containing bundles of nerve- 

 fibres (<?) ; f, terminal bundles ; g, basilar membrane ; h, spiral ligament ; i, limbus ; 

 j, membrane of Reissner ; /, Corti's organ ; m, spiral ganglion ; n, blood-vessels ; V , 

 T, M, respectively scala vestibuli, tympani, and media. 



triangular in transverse section, is attached along its base to the outer 

 wall of the bony tube, and along its narrow opposite border to the 

 projecting osseous spiral lamina ; in consequence of this arrange- 



