NATURAL SCIENCES OF PHILADELPHIA. 175 



genera. D. fuliginosa itself would be hardly separable were it not for the pre- 

 sence of some features radically distinct from, and not merely a modification or 

 varying combination of those presented by Diomedea proper. 



DIOMEDEA Linnasus. 



Diomedea, Linnaeus, S. N. 1758, and of authors. Type D. exulam. 

 Phcebastria, Reichenbach, Syst. A v. Type D. brachyura Temru. 

 Tkalassarche, Reichenbach, Syst. Av. Type D. melanophrys Boie. 



Under this head I shall consider all the species of Albatross except D. fuligi- 

 nosa. Its general characters have already been sufficiently elucidated. The 

 points of difference between it and Phozbetria will be found in the synoptical 

 table at the end of this article. 



Diomedea exulans Linnaeus. 



Diomedea exulans, Linn. S. N. i. 1766, p. 214 ; and of authors. PI. Enlum. No. 



23Y. Vieill. Gal. pi. 295. Gould, B. Aust. pi. 38, etc. 

 Diomedea spadicca, Gmel. S. N. i. pt. ii. 1788, p. 568. Lath. Syn. v. 1785, p. 



308, No. 2. Lath Iud. Orn. ii. 1790, p. 790. Lath. Gen. Hist. 1824, x. 



p. 52, No. 2 ; (excl. Var. B.) Banks ic. in?d. t. 25, fide Gray. Young. 

 Diomedea albatr us, Pallas, Zoog. Rosso-As. ii. 1811, p. . Forster, Desc. 



Anim. ed. Licht. 1844, p. 27. 

 ? Diomedea adusta, Tschudi, Cab. Journ. f. Ornith. 1856, p. 157, sp. 7. 



Habitat. Southern Hemisphere at large ; ranging to a considerable distance 

 north in the Pacific. 



The great size of this species renders it easy of recognition in any of its very 

 diverse plumages. I will confine myself to a description of the bill, the gen- 

 eral features of which may be taken as the standard of reference for all the 

 species of the subfamily. 



The frontal feathers form a rather obtuse angle on the forehead, whence they 

 run forward on the side of the upper mandible to a point a little posterior to the 

 root of the nostrils ; whence, with a slight backward obliquity, they extend to 

 the commissure. On the side of the lower mandible tbey come forward far 

 beyond those on the upper, and have a very convex almost angular outline. 

 This latter feature is constant, and of great value in distinguishing small exu- 

 lans from large brachyura when both are in fuliginous plumage. (Compare 

 outline as described under brachyura.) The point, of greatest extension is 

 nearly opposite the middle of the nosirils. The frontal feathers form a more 

 reentrant concavity on the forehead, and a more salient convexity on the side 

 of the lower mandible, than in any other species except fuliginosa. 



By gentle maceration in warm water, into which a little potassa or soda has 

 been thrown, the various corneous elements of the bill readily separate from 

 it and from each other, so that we can advantageously study them. 



The " culminicorn" is transversely broad a >d rounded, but may be some- 

 what compressed or even a little cannated ; a great difference in these 

 respects being observable in a large series of bills. Its dorsal outline descends 

 in a nearly straight line from the base to the middle of the bill; whence it 

 more rapidly rises with much concavity to the base of the UDguis. Its inferior 

 border is curved with a convex border from its distal extremity to the 

 nostrils ; then a considerable concavity is formed by the cutting away of a 

 space for the emergence of the nostrils. Behind these, it again dips down with 

 a salient convexity to join the upper edge of the latericorn ; their union, how- 

 ever, being rather a point than a line. The outline of the base corresponds 

 with that of the frontal feathers above given; and there are usually found a 

 few corrugations parallel with this outline. The distal extremity is more or 

 less fused with the superior unguicorn or dertrotheca, especially on the median 

 line of the culmen. 



The " latericorn " corresponds in its superficies with the shape of the mandi- 



3 866.] 



