218 STRUCTURE OF THE COCHLEA. [BOOK in. 



substance round the nucleus is prolonged downwards as a thin 

 process to or towards the tympanic lip and beginning of the basilar 

 membrane and upwards also as a thin process, which running by 

 the side of the inner hair-cells, ends apparently in a cuticular 

 expansion. The nuclei may therefore be considered as belonging 

 to supporting or subsidiary structures. The row of inner hair- 

 cells abuts, on the inner side, on the heads of the inner rods, 

 which thus afford a support to them on this side. On the other 

 side, towards the spiral lamina, the hair-cells are supported by the 

 elongated epithelial cells mentioned above as continuous with 

 those lining the spiral groove and also by the supporting cells 

 of the nuclear layer, the processes of the latter apparently passing 

 also in between the hair-cells in the row, for the hair-cells though 

 near together in the row do not absolutely touch. 



835. The outer hair-cells are arranged as we have said in a 

 series of rows between the outer rods of Corti and Hensen's cells, 

 the number of rows along the greater part of the spiral being, in 

 man, four. Each row is almost exactly like the others, and the 

 description of any one row will apply to all the others. We have 

 hitherto spoken of the cells as simply outer hair-cells, but each 

 row is composed not of single cells in a file, but of twin cells or 

 of pairs of cells. In each pair we may recognize a cell which bears 

 hairs (or rather rods), the hair-cell proper, or cell of Corti (Fig. 

 180 C. G.c.) and a cell which does not bear hairs (or rods) the cell 

 of Deiters (D.c), the two cells in each pair being in close apposition 

 or according to some observers actually united. 



The cell of Corti very closely resembles an inner hair-cell. 

 The body is flask-shaped, and ends in a blunt cone at some 

 distance below the reticulate membrane, between it and the 

 basilar membrane ; near its end is placed a large spherical 

 nucleus. The cell-body appears granular, especially at its lower 

 part, but the granules seem to be superficial in position, and the 

 greater part of the interior of the body appears to be of a fluid 

 nature : hence the cell readily shrinks and becomes deformed 

 under the influence of reagents. The upper end, circular in form, 

 projects through, and is as it were grasped by a ring of the 

 reticulate membrane (Fig, 180 D), and the free surface bears, like 

 the inner hair-cell, a row of short rods, but these are arranged as 

 a distinct horse-shoe or a semicircle, with the hollow of the curve 

 looking inwards. The top portion of the cell supplies a hyaline 

 border, and immediately below this is placed a peculiar nuclear 

 looking body, called "Hensen's body" (Fig. 180 C x.). 



The cell of Deiters (Fig. 180 C. DC.) consists of a cell-body, the 

 median portion of which is placed at the level of the lower end 

 of the cell of Corti, so that this seems to rest on or according to 

 some to be fused with it. From this body there stretches upwards 

 a tapering process (Fig. 180 C. php), which joins the overlying 

 reticulate membrane, and becomes attached to the phalangar bar 



