26 SMITHSONIAN MISCELLANEOUS COLLECTIONS [voL. 48 
14. The distance between the curved fibers in the functional 
remiges of all classes of birds varies only between 30 and 40 p. 
15. The powerful development of the ventral hornridge of the 
secondary quills in Diomedea and Aquila is doubtless functionally 
related to the sailing flight of these birds. 
16. The teeth on the outer vane of the first hand remiges in the 
Striges and Caprimulgi, and the down on the upper surface of the 
remiges of these birds formed by the lengthened, distal portions of 
the hook-fibers deaden the sound of the flight of these night birds. 
IV. List or AuTHORS CONSULTED AND QUOTED 
Ahlborn, F. 
1896 Zur Mechanik des Vogelfluges. Hamburg, 1896. 
Beddard, F. E. 
1898 The Structure and Classification of Birds. London, 1808. ° 
Clark, H. L. 
1894 The Pterylography of certain American Goatsuckers and Owls. Proc. 
U. S. Nat. Mus., v, 17, pp. 551-572. 
Clement, C. 
1876 Note sur la Structure microscopique des Plumes. Bull. Soc. Zool. 
France, I, 1876, pp. 282-286. 
Cuvier, G. 
1809 Lecons d’Anatomie comparée. Recuillées et publiées par C. Dumeril, 
TTP. 603 (ck Mem: id) Wins). 13')330)). 
Davies, H. R. 
1889 Die Entwickelung der Feder und ihre Beziehung zu anderen Integu- 
mentbildungen. Morph. Jahrb., Bd. 15, pp. 560-645, Taf. 23-26. 
de Meijere, J. C. H. : 
1895 Ueber die Federn der V6gel, insbesondere tiber ihre Anordnung. 
Morph. Jahrb., Bd. 22, pp. 562-591. 
Fatio, V. 
1886 Des diverses modifications dans les formes et la coloration des plumes. 
Mem. Soc. Phys. et Hist. Nat. Genéve, T. 18, Part 2, pp. 249-308. 3 pls. 
Gadow, H. 
1882 On the color of Feathers as affected by their Structure. Proc. Zool. 
Soc., London, pp. 409-421, Pl. 27, 28. 
Haecker, V. 
1890 Ueber die Farbe der Vogelfedern. Arch f. mikr. Anat., Bd. 35, Hit. 
I, pp. 68-87, Taf. 4. 
Haecker, V., und Meyer, G. 
1901 Die blaue Farbe der Vogelfeder. Zool. Jahrb., Abth. Syst. Geog. und 
Biol. d. Tiere, Bd. 15, Hft. 2, pp. 267-294, Taf. 14. 
Heusinger, C. F. 
1882 System der Histologie. Bd. 2, p. 207. 
