No. I.] THE VERTEBRATE EAR. g/ 



base, was dome-shaped, though, as Dr. Kuhn's figures show his 

 preparations, this was by no means the constant form. Some of 

 his figures, as Fig. 38, PI. XX, show a form of "cupula" which 

 was doubtless produced by the separation of the hair tuft near 

 the apex of the crista, from which line of separation they fell 

 flat to the floor of the chamber either way, forming in this 

 manner a bilobed cupula that certainly does not appear " ter- 

 minal." In the fresh cupula, Kuhn never saw the fibrous 

 structure which appears in most hardened preparations, though 

 not in all. He considered the fresh cupula to be composed of 

 a homogeneous, more or less glassy, transparent, and refractive, 

 gelatinous matter of slight resistance, in which no trace of stria- 

 tion was present. In most other matters of detail, Kuhn agreed 

 with the previous investigators who had gone over the matter, 

 Lang, Clason, Retzius, Meyer, and others ; but he did not 

 accept the conclusions of Hensen and Cissow. Kuhn separated 

 the fibres of the cupula by teasing, and, as his figures show, 

 obtained bodies of the shape and size of the terminal portions 

 of the ampullar hairs. 



Hensen (1878, 131) renewed his studies of the auditory hairs, 

 and arrived at the following results : — 



{a) In embryo Teleosts {Gobhis RiUhenspari'i, minor and mi- 

 crops) from 40-45 mm. length, the hairs of the crista acustica 

 project nearly if not quite across the ampulla (in length conse- 

 quently equa? to the diameter of the ampulla), and hence bear 

 entirely different relations to the ampullar structures from those 

 described by the authors who have touched upon this subject. 



ip) In the living condition and in fresh preparations there is 

 no ampullar cupula terminalis to be found. 



if) It is impossible that any solid matter is present within 

 the ampullar above or among the hairs, for these may be seen 

 to become applied so closely together as to leave no free space 

 between them. 



{d) On the contrary, the solid cupula terminalis is produced 

 by the action of the reagent used, e.g. hydrochloric acid and 

 alcohol (Lang), which causes the hairs to disappear as such, and 

 converts them into gelatinous substance or a thick mucous liquid. 



Retzius (188 1, 237) described many capulse terminales in the 

 first volume of his extensive monograph on the ear of verte- 

 brates, and held to his original views, extending his observations 



