SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 48, PL. XI 
21. Asecondary quill with hook and curved fibers of Columba livia Magnified 1:60 
22. Hook-fibers of a secondary quill of Columba livia. Magnified 1:110 
23. Surface view of the upper side of a hand-remex of Cygnus olur, showing the terminal parts of the 
hook-fibers. Magnified 1:270 
