176 BIRDS OF THE 
the sexes in this species. As I have mentioned already, 
one of my adult white billed males has the superciliary 
stripe white, while in the other it is gray, and the same 
is the case with the white-billed specimens of this species 
in the Leyden Museum, while one of these latter has no 
superciliary stripe at all. The black-billed specimens in the 
Leyden Museum have, as a rule, the eyebrow gray, but 
three specimens, one from the Continent, one from Banka 
and one from Sumatra (the specimen described by Vorder- 
man in his above quoted paper) have broad, pure white 
eyebrows. For this reason I cannot consider the color of 
the eyebrow a sexual character. Young birds are easily 
recognized by having the white terminal part of the tail- 
feathers spotted with black. 
Hab. South-eastern part of the Continent, Sumatra, 
Banka and Borneo. 
59. Cranorrhinus corrugatus. 
Buceros corrugatus Temm. Pl. Col. II, pl. 531 [2] (1832). 
Buceros gracilis Temm. Pl. Col. II, pl. 535 [9] (1832). 
Cranorrhinus corrugatus Salvad. Ucc. Born. p. 86; Everett, L. B. 
Born. p. 163. 
An adult male from Poelau and an immature male from 
the Upper Mahakkam. — Iris blood-red, bare skin round 
the eye sea-green, bare chin and throat Naples-yellow, 
bill orange-yellow, base of upper mandible and the entire 
casque blood-red, feet dark grayish green, soles yellowish 
gray. 
Hab. Malay Peninsula, Sumatra and Borneo. 
60. Buceros rhinoceros, 
Buceros rhinoceros Linn. Syst. Nat. I, p. 158 (1766); Everett, L. B. 
Born. p. 162; Sharpe, Ibis 1890, p. 14. 
Buceros rhinoceroides Salvad. Ucc. Born. p. 87. 
Two specimens from Mount Kenepai, one from Mount 
Liang Koeboeng and a young female from the Upper 
Mahakkam (November 1898). — Iris in the male red, in 
the female white, base of bill and casque black, rest of 
Notes from the Leyden Museum, Vol. X XI. 
