DESCRIPTION OF PLATES. 

 PLATE 1. 



1. Photograph of transverse section through tympanic wall of cochlea near apex. New-born dog. Fixation, tri- 



chloracetic aciil; stain, iron hematoxylin, Congo red. 



2. Photograph of transverse section through second turn of spiral duct. Pig embryo 93.5 mm. Trichloracetic 



and; iron hematoxylin, Congo red. 



3. Photograph of transverse, slightly oblique section through the greater and lesser ridges of second turn of cochlea, 



N'ew-born dog. Trichloracetic acid; iron hematoxylin, Congo red. 



4. Photograph of section tangential to surface of the two epithelial ridges in second turn of cochlea. New-born 



dog. Trichloracetic acid; iron hematoxylin, Congo red. 



5. Photograph of section tangential to surface of the two epithelial ridges between second and third turn of cochlea. 



New-born dog. Trichloracetic acid; iron hematoxylin, Congo red. 



0. Photograph of section tangential to surface of crista spiralis and the greater epithelial ridge. Pig embryo 137 mm. 

 Bouin's fluid; iron hematoxylin, Congo red. 



7. 7'. Photographs of a section tangential to the surface of the organ of Corti in the adult bat (Vtsjiertilio fuscus) 



Bouin's fluid; iron hematoxylin, Congo red. 



8. Photograph of section tangential to surface of crista acustica. New-born dog. Trichloracetic acid; iron hema- 



toxylin, Congo red. 



9. Photograph of section tangential to surface of crista acustica in adult bat (Vesperlilio fuscus). Zenker's fluid; 



iron hematoxylin, Congo red. 



10. Photograph of section tangential to the surface of crista acustica in adult white rat. Trichloracetic acid; iron 



hematoxylin, Congo red. 



PLATE 2. 



11. Photograph of section tangential to surface of macula acustica. Adult mouse. Trichloracetic acid; iron hema- 



toxylin, Congo red. 



12. Photograph of section vertical to surface of the crista spiralis of second turn of cochlea. Pig embryo 127 mm. 



Bouin's fluid; Mallory's stain. 



13. Photograph of section tangential to the surface of the crista spiralis of the third turn. Pig embryo 9.5 mm. Zenker's 



fluid; iron hematoxylin, Congo red, light green. 



14. Photograph of section tangential and slightly oblique to surface of crista spiralis. Pig embryo 127 mm. Tri- 



chloracetic acid; Mallory's stain. 

 1"). Photograph of section tangential to surface of crista spiralis. Pig embryo 137 mm. Bouin's fluid; Mallory's stain. 



16. Photograph of section vertical to surface of crista spiralis. Pig embryo 127 mm. Trichloracetie acid; Mallory's 



stain. 



17, 18. Photographs of section tangential to surface of crista spiralis of the third turn. New-born dog. Trichlora- 



cetic acid; iron hematoxylin, Congo red. 



19. Photograph of section tangential to the crista spiralis. Pig embryo 127 mm. Trichloracetic acid; iron hema- 



toxylin, Congo red. 



PLATE 3. 



20. Photograph of section vertical to surface of crista spiralis. Pig embryo 190 mm. Bouin's fluid; Mallory's stain. 



21. Photograph of section vertical to surface of crista spiralis. Young dog, age 4 months. Trichloracetic acid: 



iron hematoxylin, Congo red, light green. 



22. Photograph of section tangential to surface of crista spiralis. Pig embryo 190 mm. Trichloracetic acid; iron 



hematoxylin, Congo red. 



23. Photograph of section tangential to surface of crista spiralis in adult bat (Vi-s/irrtilio fuscus). Zenker's fluid, 



iron hematoxylin, Congo red. 



24. Photograph of section tangential to surface of crista spiralis. Young dog. Bouin's fluid; iron hematoxylin; 



Congo red. 



25. 25', 26, 26'. Photographs of sections tangential to surface of greater ridge. New-born dog. Trichloracetic acid; 



iron hematoxylin, Congo red. 



27. Photograph of section tangential to surface of greater ridge. Pig embryo 93.5 mm. Fixation by uranium nitrate 



method of Ramon y Cajal. 



PLATE 4. 



28. Photograph of section tangential to surface of the two epithelial ridges and the crista spiralis and their membrana 



tectoria, between the second and third turns of cochlear duct. New-born dog. Trichloracetic acid; iron 

 hematoxylin, Congo red. 



29. 30. Photographs of sections vertical to surface of the greater epithelial ridge. Pig embryo 95 mm. Zenker's 



fluid; iron hematoxylin, Congo red, light green. 



31. Photograph of section vertical to the surface of the greater epithelial ridge. Pig embryo 95 mm. Zenker's fluid; 



Mallory's stain. 



32. Photograph of section tangential to surface of the greater epithelial ridge. Pig embryo 127 mm. Trichloracetic 



acid; iron hematoxylin, Congo red. 



33. Photograph of section tangential to surface of organ of Corti and its superficial membrana tectoria. Pig embryo 



150 mm. Zenker's fluid; iron hematoxylin, Congo red, light green. 



34. Photograph of section tangential to surface of crista spiralis. Pig embryo 127 mm. Trichloracetic acid; iron 



hematoxylin, Congo red. 



35. Photograph of section tangential to surface of membrana tectoria. Adult rat (Mus decumanus) . Bouin's fluid; 



iron hematoxylin, Congo red, light green. 



30. Photograph of section tangential to surface of membrana tectoria. Pig embryo 150mm. Bouin's fluid; Mal- 



lory's stain. 



86 



