Strono. — Development of Color in Feathers. 



PLATE 7. 



Photomicrograplis. 



Fig. 37. Portion of transverse section of feather germ from Sterna hirundo. X 300. 

 Fig. o8. Portion of longitiulinal section of blue-featiier germ from Passerinji 

 cyanea. X 4bO. 



