Mr. R. B. Sharpe's Catalogue of Accipitres. 593 



9. Iris hazel. 9. Iris a darker hazel. 



10. Bill pale bluish, darkest at 10. Bill similar, except that the 

 the tips of the mandibles, and tips of both mandibles are darker, 

 sUghtly tinged with pale yellow at and their bases (especially that of 

 the base of both mandibles. the upper mandible) more strongly 



tinged with pale yellow. 



11. Cere, pale yellowish blue. 11. Cere, clear pale yellow. 



12. Feet, dull pale yellow. 12. P^eet unaltered. 



The late Mr. Gould considered that the difference between 

 those specimens of H. candicans which show the most white 

 in their plumage and those which exhibit the least, justifies 

 the division of these species into a " light ^^ and a "dark^' race ; 

 but it has not been ascertained (so far as I know) that these 

 peculiarities are hereditary, and the multiplicity of variously 

 marked intermediate specimens seems to preclude a satisfac- 

 tory separation between the '"^ light ^' and ^'^dark" races, even 

 if these extremes of variation should prove to be hereditary. 



Such extremes of variation in the case of both the imma- 

 ture and the adult birds have been admirably depicted from 

 drawings by Mr. Wolf in Mr. Gould's ' Birds of Great Bri- 

 tain;' and excellent figures of a very dark adult and also of 

 two light- coloured specimens, one adult and one immature, 

 are given in Mr. Dresser's ' Birds of Europe.' 



Mr. Dresser's figure of an adult H. candicans "in the 

 darker and more strongly marked " phase of plumage exhibits 

 the slight bluish tinge on the white portions of the upper 

 surface, and also on the usually horn-coloured upper mandible, 

 which is noticeable in some of the more profusely barred 

 adult specimens, producing more or less of a similarity between 

 such individuals and those specimens of H. holboelli in which 

 the white interspaces between the dark cross bars of the 

 mantle are especially conspicuous. 



Some of the darker immature specimens of H. candicans 

 are remarkable for the tinge of buff which pervades the lighter 

 portions of their upper surface, and of which traces, especially 

 about the edge of the wing, are also perceptible in some 

 adult and partially adult specimens of H. islandus and H, hol- 

 boelli, especially the latter. An immature male of H. candi- 

 cans from Labrador, which is preserved in the Norwich 



