DEVELOPMENT OF THE MEMBRANA TECTORIA 



431 



being more effectual than any stain. Nuclei were demonstrated 

 with haematoxylin and for counter stains eosin, orange G, and 

 acid fuchsin were employed. 



DESCRIPTIOX OF STAGES 



Aside from the thickening of the basal epithehum, stages up 

 to 4 mm. show no important changes. 



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Fig. 2 Section through the second turn (fig. 13) of cochlear duct from a 5.5 cm. 

 fetus, showing basal epithelium and origin of membrana tectoria; inner or axial 

 side to left; m.vest., membrana vestibularis; m.tect., membrana tectoria; gang.sp., 

 spiral ganglion; t.sp., spiral tunnel. Oc. 4, Obj. 4. 



5.5 cm. stage. Here we have the basal epithehum composed 

 of pseudo-stratified columnar cells (fig. 2). 



The nuclei of the high columnar cells show a division into 

 an inner and outer group wPiich correspond to the greater and 

 lesser epithelial thickenings of Rickenbacher. A section through 

 the cochlea of a somewhat later stage shows the topography of 



