178 Irving Hardesty 



EXPLANATION OF FIGURES. 



Abbreviations in common. 



Ac, accessory tectorial membrane. 



Hs., Hensen's stripe. 



Iz., inner zone of tectorial membrane. 



Lv., Labium vestibulare. 



Mb., Basilar membrane. 



Mv., Vestibular (Reissner's) membrane. 



St., Scala tympani. 



Fig. 1. — Representing unsbruuken appearance of an entire tectorial mem- 

 brane teased from the cochlea of a pig two weeks old. Under surface upward. 

 Shape constructed from measurements from several specimens and from 

 study of specimen represented. Drawn with coil more open than normally 

 to avoid overlapping of edges in apical turns. Arrangement of fibers drawn 

 in from specimen. 



Fig. 2. — Block from first half-turn of whole specimen. Viewed from under 

 surface. Cut end showing course of fibers is added from study of sections 

 of other membranes. Li., line of impression of edge of labium vestibulare. 



Fig. 3. — Block from third half-turn of whole specimen, imder surface up- 

 ward, showing course of fibers and appearance of accessory membrane as 

 torn loose from main body. Li., line of impression of edge of labium vesti- 

 bulare ; Lr., portion of lamina reticularis removed from labium with inner 

 zone of tectorial membrane. 



Fig. 4. — Block from fifth ha If -turn of whole specimen, showing the general 

 course of the fibers as viewed from the upper surface, and indicating the 

 character of cleavage in a broken end of the membrane. S., slivers of fibers 

 and matrix formed in the breaking. 



Fig. 5. — The end of the basal coil of the tectorial membrane, showing the 

 outer edge of the accessory membrane coinciding with the outer edge of the 

 main body, and showing how the inner zone (Iz.) or the attached portion of 

 the membrane curves so as to constitute the tip of the termination. 



Fig. 6. — Vertical section of the tectorial membrane in position and througli 

 the first half-turn of its coil, showing the extent to which its outer edge 

 projects beyond the organ of Corti and the course and arrangement of its 

 fibers. Pc, peripheral condensation interpreted as produced by the shrinkage 

 action of the reagents ; Vs., vas spirale, here a f)lexus instead of a single 

 vessel ; Ss., spiral sulcus. 



Fig. 7. — Vertical section from third half-turn of same cochlea as Fig. 6. 

 with the organ of Corti represented entire and showing the character 

 of the epithelium of the spiral sulcus iSs.) and an appearance on the under 



