120 THE MEMBRANOUS LABYRINTH, BY PROF. RUDINGER. 



The vesicular structureless bodies which occur both upon 

 the auditory hairs of the crista acustica, as well as closely com- 

 pressed upon the epithelium of the planum senilunare, are 

 particularly striking objects. I have observed them best in 

 specimens of Cyprinus that have been macerated in perosmic 

 acid. They here form an Uneven layer covering the whole 

 extent of the inner surface of the epithelium. (See fig. 315.) 

 In these Fishes the auditory hairs appear sometimes to be held 

 together by a glutinous material, a regularly shaped conical 

 process (cupula terminalis) being observable on the epithelial 

 surface of the ampullary crest (fig. 315), which in some of my 

 preparations occupies more than two-thirds of the ampullary 

 cavity. This is faintly striated, the striae converging from the 

 base towards the apex. The striae, however, do not appear to 

 be present in all parts of the eminence; for if the centre be 

 brought into focus, a finely granular substance comes into view. 

 Occasionally I have thought I have observed a cap upon its 

 apex, composed of delicate cells. Lang has denied the exist- 

 ence of auditory hairs in the Cyprinoids, and in place of them 

 has described the eminence itself as the terminal apparatus 

 of the ampullary crest. I believe I can recognise in this the 

 adherent auditory hairs. This subject is certainly worthy of 

 further investigation. 



Finally, two parts connected with the sacculus require to 

 be mentioned, namely : 



(1) The aquceductus vestibuli. 



(2) The canalis reuniens. 



Bb'ttcher has recently directed attention to the former. The 

 process which extends from the posterior surface of the pars 

 petrosa towards the vestibule, and lies in the so-called aquse- 

 ductus vestibuli, has already long been known, and has been 

 described at a remote period as the aqueduct of the vestibule. 

 Bottcher has recognised the existence in this process of an 

 epithelial canal, which is surrounded by nucleated connective 

 tissue, and is lined on its uneven internal surface by vascular (?) 

 tesselated epithelium exhibiting great similarity to the stria 

 vascularis of the cochlear canal. The simple canal lying in the 

 aquseductus terminates at the posterior surface of the pars 



