162 THE AUDITORY NERVE AND COCHLEA, BY W. WALDEYER. 



portion and rest of the cell body, which then has the form pre- 

 sented in the figure, and runs out into two peduncles. These 

 two-stalked remains of cells have been described as peculiar cells 

 by Deiters (13) under the name of "hair cells" ("Deiters' cells" 

 of Kolliker). In correspondence with the same character in 

 the internal hair cells, the upper portion of the cells -have here 

 also a thick cuticular cover, each of which is received into a 

 ring of the lamina reticularis (see the description of this part), 

 and supports the hairs. 



The external slope of the roof of the organ of Corti presents 

 many varieties in different animals. It is worthy of note that 

 in the case of Man there are four or perhaps five rows of exter- 

 nal hair cells (figs. 329 and 334) ; whilst in all the other animals 

 that I have examined there are only three rows * The hair 

 cells are moreover of very large size in Man ; their processes 

 are thick, and somewhat resemble cell protoplasm, whilst the 

 hairs are very long, and as stiff as bristles. In the embryo, a 

 closely compressed group of .columnar cells replaces the hair 

 cells, and these gradually flatten down into the epithelium of 

 the zona pectinata. Each hair cell probably results from the 

 cleavage of a columnar cell ; the two portions remaining more 

 or less firmly adherent to one another. 



With the exception of the spiral fibrous bands, to be hereafter 

 described in the account of the nerves, no other structures occur 

 between the hair cells. Sufficient notice has already been taken 

 (p. 152) of the columnar supporting cells of Hensen, lying to the 

 outer side of the hair cells (fig. 329, 7i). 



A peculiarity that still remains to be mentioned is the abundance of 

 clear brown pigment cells which in Man are especially found in the 

 laminae of the lamina reticularis, as well as in the epithelium, of the 

 ductus cochlearis, and in particular on the stria vascularis. Corti 

 (10, p. Ill) has already called attention to them. 



* Hensen (27) remarks, without stating whether in Man or in animals, 

 that in the second or third turn there appear to be " more than four hair 

 cells." Lowenberg depicts (fig. 4) four brushes of hair in a transverse 

 section of the organ of Corti from a child, but says nothing respecting 

 the presence of four rows of hair cells in Man, either in the text or in the 

 explanation of the plates. 



