NERVES AND EPITHELIUM OF AMPULLA AND SACCULI. 117 



also consider the auditory hairs as gradually attenuating 

 processes of the flask-cells. These run up between the colum- 

 nar epithelial cells by which the latter are supported, occupy- 

 ing the angular interspaces between their borders. It may 

 further be remarked that though the auditory hairs do not 

 become black in perosmic acid, yet they assume a brown tint 

 earlier than any other tissue in the walls of the ampullae. 



The nerve epithelium of the ampullae and sacculi thus presents 

 a number of columnar supporting cells, between which are 

 spaces and fine canals for the reception of the fusiform nerve 

 cells, which last are to be regarded as bearing the terminal 

 organs of the vestibular nerves. The observations of F. E. 

 Schulze on a transparent fish (Gobius niger ?) may here be 

 mentioned, according to which the primitive nerve fibres are 

 directly continuous with the auditory hairs. The stage of 

 development of the animal from which his drawing was taken 

 is such that the epithelial cells are probably not yet apparent. 



According to Max Schultze and C. Hasse, stellate and par- 

 tially pigmented cell forms occur in various classes of animals, 

 situated between the simple columnar cells, in the neighbour- 

 hood of the nerve eminence of the crista acustica and of the 

 macula acustica. The details of the special disposition of 

 these cells is to be found in the beautiful treatises of those 

 authors. 



As regards the auditory hairs, the first observations upon 

 the presence of ciliated epithelium in the membranous labyrinth 

 were made by Ecker, Reich, and Leydig; but the true nature of 

 the auditory hairs was first pointed out by Max Schultze. 

 This observer described them as forming long stiif fibres which, 

 gradually becoming more and more attenuated, are attached 

 by their base to the nerve epithelium, and project into the fluid 

 of the endolymph by their fine-pointed extremities, unless in- 

 deed, as I imagine, their extremity is covered by a peculiarly 

 organised cap. That structure, which was observed and has been 

 depicted by Leydig in the ampullae of the Pigeon, I, with Max 

 Schultze, regard as the detached epithelial investment of the 

 crista acustica and its vicinity. In Fishes and Birds, however, 

 I have observed a delicate structure composed of remarkably 

 fine cells in that tract of the ampulla on which the auditory 



