FALCONIDaE — THE FALCONS. 105 



10. Antenor. Form heavy, the wings and tail moderately long, 

 and feet very robust ; bill rather elongated, the commissural lobe 

 prominent, and the base of the culmen somewhat depressed. 

 Fourth quill longest; outer five with inner webs cut. Lores 

 naked, and almost destitute of bristles. 



IL Onychotes. Outstretched feet reaching beyond end of tail; 

 tibial plumes short, close, not reaching below the joint. Wing 

 short, rounded, very concave beneath, the fourth quill longest; outer 

 five with inner webs sinuated. Tail short, but little more than half 

 the wing, slightly rounded. Claws very long, and extremely acute. 



12. Asturina. Bill and feet as in Antenor ; lores densely 

 bristled ; wing short, rounded, concave beneath, the third to fourth 

 quills longest ; outer four with their inner webs cut. 



13. Buteo. Form of Antenor^ but primaries longer and more 

 pointed, the fourth usually longest, and the outer three or four with 

 inner webs cut. Bill and feet as in Asturina. Tail moderate, or 

 rather short, nearly even, or slightly rounded. 



^^ Front of the tarsus densely feathered down to the base of the toes.' 



14. Archibuteo. Feathering of the tarsus interrupted behind 

 by a bare strip along the full length ; middle toe less than half as 

 long as the tarsus. Nostril broadly oval, obliquely horizontal ; 

 bill weak, the upper outline of the cere much ascending basally. 

 Feathers of the nape normal, blended. Third to fourth quills 

 longest ; outer four or five with inner webs cut. 



15. Aquila. Feathering of the tarsus uninterrupted behind; mid- 

 dle toe more than half as long as the tarsus. Nostril narrowly 

 oval, obliquely vertical ; bill strong, the upper outline of the cere 

 nearly parallel with the lower. Feathers of the nape lanceolate, 

 distinct. Fourth quill longest ; five to six with inner webs cut. 



** No trace of membrane between outer and middle toes. 



16. Haliaetus. Tarsus feathered in front one third, or more, of 

 the way down ; the naked portion with an imperfectly continuous 

 frontal, and less well defined posterior, series of transverse plates, 

 and covered elsewhere with roundish granular scales. Feathers of 

 the neck, all round, lanceolate, distinct. Bill Very large, the choixl 

 of the culmen more than twice as long as the cere on top ; nostril 

 oval, obliquely vertical. Third to fifth quills longest; outer six 

 with inner webs cut. Tail rounded or cuneate, sometimes con- 

 sisting of fourteen feathers. 



The foregoing diagnoses embrace merely the more conspicuous external 

 characters whereby the genera may be most readily distinguished by the 

 student. The following table presents additional accompanying characters 

 afforded by the osteological and anatomical structure, of more importance 

 in defining with precision the several groups embraced in our fauna. 



A. Scapular process of the coracoid produced forward so as to meet the clavicle * 

 (Huxley). Nasal bones almost completely ossified, the nostril being a small, 

 usually circular opening, with a raised or " rimmed " margin, and conspicuous, 

 usually central, bony tubercle. Inferior surface of the supermaxillary bone with 



As in all the Strigidcc. 



VOL. III. 14 



