g2 AYERS. [Vol. VI. 



fibrous) parallel with the long axis of the cochlea. The rounded 

 end appears frequently canal-like, in which Kolliker thought he 

 detected a blood-vessel in a few preparations. 



Boettcher (1859, 35) defends his former views relative to 

 Corti's membrane. He recognizes two zones, an inner and an 

 outer. The inner is extremely pale, with pronounced cell mark- 

 ings (impressions). External to the acoustic teeth the second 

 and thicker zone begins. It is very thickly and finely striated. 

 On the external border of the latter zone one frequently finds 

 broad branching fibres, which usually form the border, then 

 bending at right angles are dissipated in a brush of branches, 

 which pass inward and are lost in the fine striation. Not far 

 from the border one frequently sees a seam which may perhaps 

 mark the line of insertion of the third zone. Boettcher also had 

 preparations which showed even a second membrane running 

 across the scala media into the cochlear wall. 



Deiters (i860, 69) described this structure as follows : " Corti's 

 membrane does not begin at the apices of the cells, but passes 

 on beyond them ; but beyond the apices it is fine, transparent, 

 and scarcely striated. External to the teeth it shows a diago- 

 nal striation due to folds or fibres. The outer border of the 

 membrane really inserts on the ligamentum spirale. The upper 

 surface is covered by a simple, thin, polygonal epithelium. The 

 lower surface has none." 



Kolliker (1861, 166) studied the development of the cochlea, 

 and concluded that ontogenetically the lamina reticularis, as well 

 as Corti's membrane, are cuticular formations, both secreted 

 by the cells of the epithelial ridge, beginning in the early 

 stages of cochlear growth. 



The cochlear canal begins to develop as a purely epithelial 

 tube, and it shows on the floor which later on becomes con- 

 verted into Corti's organ, three thickenings, one large and two 

 smaller ones. The large epithelial ridge is covered by a struc- 

 tureless or, perhaps, finely striated membrane, the rudiment of 

 Corti's membrane, and it is a cuticular product of the long 

 epithelial cells. 



Hensen (1863, 130) wrote : "The membrana Cortii is secreted 

 in the embryo by a group of cells known as the Organon Kolli- 

 keri, which undergoes atrophy as the membrane increases in 

 size, and whose function in consequence seems to be that of 



