AftuiLixji. 225 



most of them subterminally black, causing a more or less distinctly 

 mottled appearance. 



Adult. General colour of upper surface ashy grey, the head and 

 neck all round, as well as the entire under surface of the body, 

 white, excepting the long crest-feathers and an indistinct chest- 

 band, which incline to ashy grey ; wing-coverts and scapulars gene- 

 rally darker ashy, slightly mottled with black, the median coverts 

 inclining to whity brown ; quiUs blackish, externally shaded and 

 mottled with greyish, the secondaries more decidedly of the latter 

 colour with black mottlings ; tail-feathers ashy brown, externally 

 shaded with ^rey, and crossed with six imperfect bands of black, 

 with which the interspaces are plentifully mottled ; biU black ; 

 feet yellow ; iris brown. Total length 38 inches, culmen 3-1, 

 wing 22-3, tail 16, tarsus 4*8. 



Hab. The same as that of the genus. 



a. Ad. st. South America, Zoological Society. 



b, c. Imm. St. British Guiana. Sir R. Schomburgk [C.]. 

 d, e,f. Skeletons. Zoological Society. 



Subfamily VI. AQUILINtE. 



Outer toe only connected to middle toe by membrane ; tibia much 

 longer than tarsus, exceeding it by more than length of hind claw ; 

 tarsus more than half the length of the tibia, and reticulate on 

 hinder aspect ; bill festooned but not toothed. 



Key to the Genera. 



a. Nostrils hidden by stiff bristles ; chin with a> 



long tuft of black bristly hairs 37. Gypaetus, p. 228. 



b. Nostrils visible ; no chin-tuft. 



a'. Tarsi clothed with feathers all round to 

 base of toes. 

 a". Tail strongly graduated, wedge-shaped 

 when closed, the middle feathers ex- 

 ceeding the outer ones by more than 



length of tai-sus 38. Uboaetus, p. 231. 



6". Tail nearly squai'e or only moderately 

 rounded, the difference in length of 

 middle and outer tail-feathers inappre- 

 ciable and less than length of tarsus. 

 a'". Distance between tips of primaries 

 and tips of secondaries greater than 

 length of tarsus. 

 a*. Claws cm-ved and powerful, the 

 outer toe with its claw exceeding 

 in length the circumference of 

 inner claw. 

 VOL. I. R 



