ANATOMICAL AND PHYSIOLOGICAL STUDIES ON 



Hardest? i'l.">, p. 54) says "that the space occupied by the 

 width of the greater epithelial ridge increases throughout the 

 coils of the cochlea up to pigs of 15 to 16 cm., and thereafter 

 it begins to decrease very perceptibly." He measured the 

 width "from the membrana propria of the epithelium of the 

 greater ridge, at its most axial extension under Huschke's teeth, 

 to the apical end of the inner hair cell of the spiral organ." The 



TABLE 46 



Vertical distance from the membrana basilaris to the surface of the pillar cells — on 



age (chart 20) 



Ratios 1 — 12 days 



1— 20 " 



1—546 " 



12—546 " 



20—546 " 



1.3 

 1.7 

 1.6 

 1 3 

 10 



method of measurement differs from mine, so the results cannot 

 be compared directly. While the distance in the rat increases 

 nine days of age, that in the pig decreases perceptibly in 

 fetuses more than 16 cm. long. 



According to Hardesty ('15, p. 55). "the decrease in the I 



and III half turns may be as much as one-third of the width 



of the greater ridge when at its maximumsize and activity. " 



alter the tectorial membrane is about completely produced, 



