PLATE 3 



EXl'LANATION OF FIGURES 



5 Section of 3rd half turn of cochlear duct of pig of 5.5 cm., showing thick- 

 ening of epithelium of axio-basal side and beginning of tectorial membrane. 



6 Section of 3rd half turn of cochlear duct of pig of 9 cm., showing lesser 

 epithelial ridge and the fibrils produced by it, and advancement in production 

 of the tectorial membrane. 



7 Section of 3rd half turn of developing tectorial membrane and differen- 

 tiating spiral organ of pig of 14 cm. 



68 



