Strong. — Development of Color in Feathera. 



PLATE 2. 



All Figures magnified 495 diameters. 



Fig. 10. Transverse section of barb from blue featlier of Cotinga cayana. 



Fig. 11. Transverse section of l)arb from l>lue wing-featiier of Pitta molnccensis. 



Figures 12-14 are portions of transverse sections of wing-featliers from Sterna 

 liirundo. 



Fig. 12. Section at level of 12 in Fig. 1. The position of the part of the section 

 here siiown is indicated in Figure 2 by tiie asterisk (*). crs". Small 

 ridge in epithelium preceding formation of barb ridges. 



Fig. 13. Section at tiie level 13, in Figure 1. cl'. Dividing cell. 



Fig. 14. Section at the level 14 in Figure 1. 



