366 MANUAL OF HISTOLOGY. 



prolongations shaped a little like the bones of the fingers, and 

 hence called phalanges (Fig. 163, Kp). These enclose spaces be- 

 tween them, through which the ends of the hair-cells project. 

 The network thus formed is called the lamina reticularis, and 

 gives a very peculiar appearance when this portion of the organ 

 is viewed from above. 



Corresponding to the pillars are rows of hair-cells termed 

 inner and outer a single row of the former (Fig. 163, a) and 

 four rows of the latter (Fig. 163, a", a", a"). The shape of 

 the cells of the inner row is cylindrical, having their base pro- 

 longed into a fine thread expanding into a foot-stalk, which 

 passes into the membrana basilaris. The top of the cell which 

 passes through the opening in the lamina reticularis is pro- 

 vided with fine cilia. The four rows of cells in connection with 

 the outer pillar are of the same shape as those of the inner 

 row, but, in addition, are joined at their lower part to peculiar 

 cells shaped like a flask, large and rounded at the bottom, and 

 tapering to a long and narrow neck. The tops of these cells 

 reach to the lamina reticularis, but do not pass through it 

 (Fig. 163, r, r, r, and &). Immediately adjoining the outer rows 

 of hair-cells are several rows of cylindrical epithelial cells (Hen- 

 son's prop-cells) (Fig. 163, Hz), which pass gradually into the 

 short cubical epithelium forming the zona pectinata (Fig. 163, 

 Zp to Zp f ) adjoining the epithelial lining of the ductus cochle- 

 aris. 



The course of the nerve has already been followed to the 

 ganglion spirale. From this point a number of fine trunks 

 pass through a canal in the osseous portion of the lamina spi- 

 ralis to the lower lip of the crista, which they leave as naked 

 axis-cylinders by a number of small holes, called the habenula 

 perforata (Fig. 163, Hn). After entering the ductus cochle- 

 aris they divide into two chief bundles, one distributed to the 

 inner hair-cells, arid the other, passing between the bases of 

 the inner pillars, crosses the tunnel and then again passes be- 

 tween the outer pillars, and terminates finally in the outer 

 hair-cells. Beyond the fact that they apply themselves directly 

 to the surface of the hair-cells, their mode of ultimate ending 

 is not known. 



From the upper edge of the crista spiralis, lying directly 

 upon it and covering the whole of the organ of Corti, is the 

 membrana tectoria (Corti' s membrane) (Fig. 163, Mt), a homo- 



