The Nature of the Tectorial Membrane 133 



vestibulare across to the outer edge of the membrane, the greater 

 number of them at least course varying distances across, then curve 

 downward and, still curving, reach the under surface, where they ter- 

 minate, many running a short distance parallel to the under surface, 

 prior to termination. The shape of the bluntly rounded, outer edge 

 of the membrane is determined by the curvature downward of the 

 outermost of the fibers. The outline of this edge is never perfectly even, 

 but always appears finely and irregularly scalloped, as shown in Fig. 3, 

 suggesting that the fibers may have a tendency to course and curve 

 around the edge in bundles. In some of my preparations the under 

 surface of the outer edge of the sections at the apex (similar to Fig. 6) 

 appeared thickly studded with the down-hanging ends of fibers as 

 though the under surface had been frayed either by the tearing away of 

 the peripheral condensation or by partial liquefaction of the matrix. 

 Along the inner edge, the sections show that all the fibers by no means 

 are continuous from the inner, attached zone, but that the rapid Increase 

 in the thickness of the free portion results from an enormous increase 

 in the number of fibers concerned. The interior fibers of this region 

 course and curve parallel in the main with those of the upper surface, 

 till those nearer the under surface gradually come to sweep downward 

 and then outward and parallel for short distances with the under 

 surface which they form and in which they terminate. 



Fig. 9 is made from a horizontal section of the cochlea, and repre- 

 sents a tangential section of the tectorial membrane passing about 

 parallel with the surface of the labium vestibulare and splitting 

 Huschke's teeth. It is taken from the neighborhood of the third half- 

 turn, and a comparison of it with a line drawn in the same plane through 

 Fig. 7 will make clear the relations and appearances shown by it. The plane 

 passes through the dorsal aspect of the membrane, and, as is to be expected 

 from the evident course of the fibers shown in Fig. 7, near Huschke's 

 teeth (Ht) the fibers are cut transversely and obliquely in the zone 

 indicated by a, while the fibers in the outer zone, indicated by &^ course 

 more nearly in the plane of the section. In this section the fibers do 

 not appear to run wholly parallel with each other. Apparently they 

 even anastomose, and where they are cut transversely, they appear to 

 be connected with each other by fine collateral filaments. How much 

 this specimen was shrunken and how much this appearance is due to 

 the reagents cannot be determined. The tangled appearance is no doubt 

 due largelv to shrinkage and coagulation effects. The fine filaments 



