NATATORES. SULA. 453 



PLATE 86. Represents a Male of this species (killed near the 

 Fern Islands) in the nuptial plumage, or with the fron- 

 tal crest fully developed. Natural size. 



Head, neck, lower part of the back, and under plumage, General 

 fine silky blackish-green. Upon the forehead is a tuft tkm. P 

 of blackish-green elongated feathers, upwards of two Summer 

 inches long, and curving forwards. Mantle, scapulars, * 

 and wing-coverts deep-black, bronzed green, each fea- 

 ther being surrounded by a band of velvet-black. Tail 

 consisting of twelve feathers, scarcely six inches long, 

 black, with the shafts strong and elastic; the webs 

 coarse, and generally much worn at their tips. Legs 

 and toes black. Guttural skin and corners of the mouth 

 gamboge-yellow, the former having black specks. Bill 

 black ; two inches and three-eighths in length from the 

 forehead to the tip. 



In autumn, and the early part of winter, it is destitute of 

 the frontal elongated feathers, but in other respects the 

 plumage is the same as in summer. Both sexes are 

 nearly alike. The young of the year have the head and Young. 

 neck of a greyish-black, tinged with green, and the un- 

 der parts are more or less mixed with greyish-white. 

 The upper plumage inclines to greenish-brown, and the 

 zone that margins each feather is broader than in the 

 adults. 



GENUS SULA, Burss. GANNET. 



GENERIC CHARACTERS. 



BILL longer than the head, thick, strong, strait, acumi- 

 nate, compressed towards the point, with the dertrum slightly 

 convex. Mandibles equal ; the upper one laterally sulcated 

 from the base to the tip, and with a hinge near the posterior 

 part, making it to appear as if composed of five separate 

 pieces. Culmen rounded. Lower mandible having the 



