COCHLEA OF BIRDS AND AMPHIBIA. 



181 



columnar form, slightly ventricose below, and prolonged into 

 a long process. The upper extremity supports a large brush 

 of fine stiff hairs, which are of considerable length. Deiters 

 (14) and Hasse (20) admit, as Leydig (36) also did at an earlier 

 date, the presence of only a single strong and long hair upon 

 the terminal surface of the cells, instead of the brush or tuft of 

 hairs, and still adhere to this unquestionably erroneous view, 

 notwithstanding that some of their own observations show 

 that this apparently solid hair exhibits traces of a division 

 into separate filaments. In accordance with this they name 



Fig. 336. 



f i 



Fig. 336. Isolated cells from the cochlea of a Pigeon, magnified 800 

 diameters. Fresh specimens, with the addition of 0'5 per cent, solu- 

 tion of common salt. A B 0, Hair cells ; A and B, profile view ; (7, 

 view of the terminal surface ; a, tuft of hairs ; 6, clear cup-like spot ; 

 c, nucleus, with nucleolus ; d, basal process, with dark fibres extending 

 to the nucleus ; D, a group of small cell-like structures, g, con- 

 nected by stalk-like processes to a tooth cell, / ; e, hair cell ; E, teg- 

 mental cell ; w, dark granulated and nucleated cell body, with clear 

 extremity, n. 



the structures in question "rod cells," a term that I shall 

 exchange for " hair cells," in consequence of the close resem- 

 blance they exhibit to the internal hair cells of Mammals. In 

 surface views the hair tuft appears to project from ar cup-like 

 depression of the cells, and to extend inwardly as far as to the 

 nucleus. The upper (free) extremity of the cell presents a 

 cuticular hem or border. I have sometimes seen a fine thread 

 extend from the nucleus to the basilar process of the cell. 



