30 
SMITHSONIAN MISCELLANEOUS COLLECTIONS 
Key To LETTERING, WHICH APPLIES TO ALL FIGURES. 
Curved fibers. 
Terminal thread. 
Ledge below the point of origin of the tertiary fibers. 
Hooks of the hook-fibers. 
Hook-fibers. 
Ventral hornridge of the secondary quill. 
Horny substance. 
Primary quill. « 
Nuclei of the cells forming the tertiary fibers. 
Crests on the ledges of the secondary quills. 
Medullary substance. 
Groove in the upper margin of the curved fibexs. 
Dorsal thickening of the secondary quills. 
Processes of the ventral membrane of the hook-fibers. 
Processes of the ventral membrane of the curved fibers. 
Spines of the hook-fibers. 
Dorsal lobes of the hook-fibers. 
Teeth on the outer edge of remiges. 
[voL. 48 
Dentate projections on the dorsal margin of the curved fibers. 
Limits of the cells composing the tertiary fibers. 
