284 



THE ESSENTIALS OF HISTOLOGY. 



The auditory hairs do not project free into the endolymph, but into 

 a soft mucus-like substance, of a dome-like form in the ampullae (fig. 

 316), and which in the saccule and utricle has a mass of calcareous 

 particles (otoliths) embedded in it. 



FIG. 318. VERTICAL SECTION OF THE COCHLEA OP A CALF. (Kolliker.) 



n sp.l 



FIG. 319. VERTICAL SECTION OF THE FIRST TURN OF THE HUMAN COCHLEA. 

 (G. Retzius.) 



s.v., scala vestibuli; s.t., scala tympani ; D.C., canal of the cochlea; sp.l., spiral lamina; 

 n, nerve-fibres ; l.sp., spiral ligament; str.v., stria vascularis ; s.sp., spiral groove; R, 

 section of Reissner's membrane ; I, limbus laminae spiralis ; M.t., membrana tectoria; 

 t.C., tunnel of Corti ; b.m., basilar membrane ; k.i., h.e., internal and external hair-cells. 



The cochlea consists of a bony tube coiled spirally around an axis, 

 which is known as the columella (fig. 318). The tube is divided 

 longitudinally by a partition which is formed partly by a projecting 



