GENESIS OF FAULT-BARS IN FEATHERS. 



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Abbreviations. 



b. fault-bar. 

 bb. barb. 

 ble. barbule. 



c. region of reduced pigmentation. 

 cap. capillaries. 



if. inferior umbilicus. 



* sh. inner sheath. 



lb. longitudinal fault-bar. 



m.b. basal membrane. 



m. modified region. 



n. nucleus. 



p. pigment cell. 

 pc. process of pigment cell. 



pi. pulp. 



rh. rhachis or shaft. 



tu. outer sheath or tunica. 



