The Xature of the Tectorial Membrane 179 



surface of the outer zone of the tectorial membrane, Ac, which is interpreted 

 as representing the much shrunken accessory membrane in section. P^., 

 below, shows what seems in the section to be a strip of the peripheral con- 

 densation torn off in the manipulation and adhering to the inner supporting 

 cells of the organ of Corti. E., endothelium lining scala tympani, St.; Vs., 

 vas (plexus) spirale. The curved shape of the section of the tectorial mem- 

 brane is due to shrinkage. 



Fig. 8. — Vertical section from seventh half-turn of same cochlea as Fig. 7. 

 The curve in the upper surface of the outer zone of the tectorial membrane 

 is explained as due to shrinkage produced by the techique as well as the 

 fact that the membrane does not appear to extend entirely over the organ of 

 Corti. From the size of the tectorial membrane, as compared with Figs. G 

 and 7, it is assumed that the section passes some distance from the basal end. 

 Lettering same as in Figs. 6 and 7. 



Fig. 9. — Horizontal section of tectorial membrane at region of second turn 

 of coil, showing appearance and arrangement of fibers as cut transversely, 

 obliquely and longitudinally. Irregularities of course of fibers explained as 

 due largely to collapsed condition produced by reagents, a., region of trans- 

 versely cut fibers; &., longitudinally cut fibers; Ep., "Epithelial cells" inserted 

 between the white fibrous tissue bundles; lit. (Huschke's teeth) of the 

 labium vestibulare. 



Fig. 10. — Vertical section from the third half-turn of a cochlea from a 

 foetal pig of 14 centimeters, showing a stage in the development of the tec- 

 torial membrane just before the beginning, along the inner edge, of the 

 retrogressive changes of the greater epithelial thickening, Get. Let., lesser 

 epithelial thickening, enlarging to form organ of Corti ; Mt., tectorial mem- 

 brane ; 8s., cells in region of what will become spiral sulcus ; other lettering 

 same as in Figs. 6 and 7. 



Fig. 11. — T'rom thin horizontal section of basilar membrane, stained by 

 Mallory's method for white fibrous tissue, showing the structure to be 

 composed of bundles of white fibers, FJ)., connected with each other by 

 numerous fibers less compactly arranged. Ls., side toward spiral ligament ; 

 Lt, side toward labium tympanicum of spiral limbtis : Fn., foramina nervosa 

 in babenula perforata. 



Fig. 12. — Portion of a line of the outer rods of Corti, adhering together 

 and showing grouping as appeared in teased specimen from second turn of 

 cochlea, a., phalanges assumed to be less resistant to downward pressure 

 than those designated by 6.; f., fibrous portion of curved foot of rod which 

 rests over basilar membrane ; Ir., fragments of inner rods left in their 

 separation from the outer ; P., granular protoplasm between rods and prob- 

 ably continuous with that forming the foot cells. 



