6t)8 STEECOEAEIUS POMATOEHIXUS, POMAEINE JAEGEE. 



The " cere" has a straight, smooth, convex culmen ; its inferior bonier curves gently 

 upward to give passage to the nostrils. The uniou of the two lateral halves leaves a 

 ■well-marked acutely-angular recess over the culmen. There is a well-marked Interal 

 longitudinal groove, denoting the uniou of that part of the eere which is attached to 

 tbe culmen, with that part which depends over the nasal fossal. Curve of nail regu- 

 lar, gradual. Commissure straight to the nostrils, then gradually declinato-convex. 

 Eauii of both mandibles divaricate at a considerable angle, making the base of the hill 

 very broad. Eminentia symphysis slightly marked ; commissure long, gouys short, a 

 little concave, gape wide. Outline of feathers on the bill much as in the LariiKv, but 

 supero-lateraliy they do not run so far forward, nor with so acute an angle. Nostrils 

 placed far forward,' lateral, liuear, direct, pervious, their opening a, little club-shaped. 

 Bill horn, deepening into black ; feet black. Pileuui and occipital crest brownish- 

 black ; this color extending much below the eyes, and occu]iying the feathers on the 

 ramus of the inferior maxilla. Acuminate feathers of the neck light yellow. Back, 

 wings, tail, upper wing-coverts, under tail-coverts as far as the flanks, deep blackish- 

 brown. Under parts, from chin to abdomen, and neck all round (except the acuminate 

 feathers), pure white. (A state of plumage not often met with. The var. "C" of 

 Temminck.) 



Kearly adult. — Generally as in the preceding, but with a row of brown spots across 

 the breast ; the sides under the wings transversely barred with white and brown; the 

 purity of the dark color of the abdomen interrupted by some touches of white. The 

 legs wholly black, and the tail feathers projecting as much as in the fully adult. (A very 

 common state of plumage, described by most authors as fully adult, Temminok's 

 var. "B.") 



Intel-mediate stage. — The band of dark spots across the breast has widened and enlarged, 

 so that the whole breast appears brown, mottled with white ; the sides under the wings 

 are conspicuously barred with white and brown ; the white of the under parts is con- 

 tinued down over the abdomen to the under tail-coverts ; the pure brown of these parts 

 which obtains in the adult, now ouly appearing as transverse bars among the white. 

 Tlie upper tail-coverts and some of the wing-coverts are barred with white. The bases 

 of the primaries are interiorly white. The contrail tail feathers now only project au 

 inch. The tarsi are quite changed in color ; they are now irregulai'ly blotched with 

 chrome-yellow — the hind toe and nail being of this color. (A very common stage, cor- 

 responding to var. "A" of Temminck.) 



I)usky stage. — The bird is very nearly unicolor ; blackish-brown all over ; this color 

 deepening into quite black on the pileum ; lightening into fuliginous brown on the ab- 

 domen, with a slight gilding of the black on the sides of the neck. The whitish bases 

 of the primaries exist. The feet are in the chromo-variegated condition. The central 

 tail feathers scarcely project half an inch. (Var. "D" of Temminck.) 



Touiig-of-the-year. — Bill much smaller and weaker than in the adult, light colored to 

 beyond the nostrils, when it becomes brownish-black. Feet aud toes mostly hright 

 yellow, the terminal portions of the latter black. The whole body is everywhere trans- 

 versely waved with dull rufous. On the head, neck, and under parts, this rufous forms 

 the predominating color ; and the bands are exceedingly numerous, of about the 

 same width as the intervening dark color. On the flanks aud under tail-coverts the 

 bars become wider, and almost white in color. On the back and wing-ooverts the 

 brownish-black is the predominating color ; and if any rufous is present, it is merely 

 as a narrow edging to the feathers. The under wing-coverts have irregularly-angular 

 transvei-se waves of brownish-black and white. The remiges and reotrices are brown- 

 ish-black, darker at their tips ; fading into whitish toward the bases of the inner vanes. 

 On the nead and neck the light rufous decidedly predominates, and seems indistinctly 

 but thickly nebulated with dusky ; this dusky forming a conspicuous spot just at the 

 anterior canthus of the eye. (In this plumage the bird is the Stercorarius striatua of 

 Brisson, and probably the Larua crepidatua of Gmelin aud Latham.) 



The above stages are gradual, and merge Into each other, so that one can without 

 difUcnlty be traced into another. As a brief exposition of the mode in which the 

 change from the young bird, in the variegated state of plumage and with particolored 

 feet, it may be stated that the light and dark colors, at first everywhere intermingled, 

 gradually grow more and more distinct, being separated by lines becoming more and 

 more trenchant, until the two colors occupy entirely diflfercnt regions of the body, and 

 are wholly separated from each other. Tiie feet gradu.illy lose their yellow blotches 

 and become black. 



If we examine Temminick's Manual of 1840, page 491, we find that he presents four 

 " varietifes " of this species. Comparison of his diagnosis of these supposed varieties 

 with the four stages of plumage characterized above, it will be seen that they corre- 

 spond. The adult plumage above described is his variety " C," of which he correctly 

 says, that it is not very olten met with. Our "nearly adult" is his variety "B;" our 

 third intermediate stage is about his variety "A;" while the fasco-unicolor state corre- 

 sponds to his " D." He early maintained the opinion that this dusky stage is entirely 

 independent of sex ; but he subsequently gives as his mature opinion that the white- 



