AVES. 59 



GENUS CATHARTES. 



Beak as in the preceding, wide and with oval and longi- 

 tudinal nostrils, but no caruncles; head and neck naked. 



GENUS PERCNOPTERUS. 



Beak long, slender and slightly inflated above its curva- 

 ture; nostrils oval and longitudinal ; only the head naked. 



TRIBE II. GYPACTOS, STORR. GRIFFINS. 



Eyes and talons as in the preceding ; head entirely co- 

 vered with feathers ; beak very strong and straight, with a 

 crook at the end, and inflated at the curve; nostrils covered 

 by stiff hairs directed forwards ; tarsi short and feathered to 

 the toes. One species only. 



TRIBE III. FALCO, LIN. FALCONS. 



Head and neck clothed in feathers ; a projection of the 

 eyebrows, causing the eye to appear sunk ; blood-thirsty and 

 endowed with a strength which permits them to satisfy their 

 insatiable appetite ; the female is larger than the male, and 

 on this account is called, in falconry, the tarsel or tiersel. 

 The Falcons are the tyrants of the air ; it is among them 

 that poetry has chosen the king of Birds. Two sections. 



Section I. Noble Birds of Prey. 



Beak curved from its base ; second quill of the wing the 

 longest. Two genera. 



GENUS FALCO, Bechst. Falcon proper. 



Upper mandible armed with a strong tooth towards the 

 point ; wings as long or longer than the tail. 



GENUS HIEROFALCO, Cuv. Gerfalcon. 



A simple emargination of the beak ; tail long and displayed, 

 extending remarkably beyond the wings. 



Section II. Ignoble Birds of Prey. 



Fourth quill of the wing generally the longest; beak 

 furnished about its middle with a simple emargination in 

 place of a lateral tooth towards its point. Four remarkable 

 genera. 



