Btbono. — Development of Color iu Feathers. 



PLATE 9. 



Photomicrographs. 



Fig. 41. Transverse section of green-feather germ from Passerina ciris, showing 

 pigmentation completed and cornification nearly so. X 157. 



Fig. 42. Transverse section of wing-feather from the " homer " pigeon, showing 

 differentiation and cornification completed. X 09. 



