180 PROCEEDINGS OF THE ACADEMY OF 



batross, very abundant in the North Pacific. It is readily distinguishable from 

 the young brachyiira, to which it assimilate? so closely in its plumage, by its 

 bill, which Dr. Scblegel has happily described as " tres court, quoique gros.'' 

 The shortness of the bill ; its great width, especially basally where the cul- 

 minicorn is so broad and descends so low as to overlap the Jatericorn ; the 

 general straightness of its several outlines, and its color ; the relative propor- 

 tions of the wings and tail ; and the proportions and color of the feet, all fur- 

 nish data ample for its separation from brachyura. So far as now known, the 

 fuliginous plumage above described is its only one ; but should it ever assume 

 a livery like that of /jrachi/ura, still the above points of form will readily char- 

 acterize it. The only question then is as to the came to be employed for it. 

 American writers have without exception identified the " nigripes " of Audu- 

 bon with the young brachyura. 



Unfortunately I cannot find the type specimen of nigripes among the many 

 types of other species of Mr. Audubon now in the Smithsonian Museum. I have 

 before me the types of his " chlororhyiichos " and " fusca ; " but '' nigripes " 

 has been mislaid. We have therefore onlj his description as a guide ; from 

 which we must determine whether he hnd in view the present sp'cifS or a 

 young brachyura, also found on the Pacific coast of North America. In -the 

 latter event nigripes would become a synonym, and a new name be required for 

 the species now under consideration. 



Examining the dimensions given by Audubon we find several discrepancies. 

 In general they may be stated as too large. The bill is by no means '' fire" 

 inches long, — especially along the edge of the under mandible. The tail is six 

 or more instead of " three " inches. Tue dimension given for the inner toe 

 (llfl) is doubtless a typographical error. By carefully measuring Audubon's 

 specimen of " chlororhynchos," I find that he took the curve Ci{ the cnlmen, 

 not its chord. Applying this test to the specimens before me they measure 

 4-50 to 4-75 inches; which is sufficiently near the dimensions he states. But 

 five inches along the edge of the under msudible is too great, even for the 

 mfljority of adult brachyura ; while three inches as the length of tail, is wide of 

 the murk for either species. Eliminating palpable errois however, there is 

 nothing in his description or measurements absolutely incompatible with the 

 present species, though much confirming a suspicion that he may really have 

 had a young brachyura in view ; and 1 therefore think it best, at least until his 

 type can be found, to accept his name, now well established, for this species, 

 especially as the necessity for a new one will thereby be obviated. 



DiOMEDEA GIBBOSA Gould. 



I), gibbosa, Gould, Ann. Mag. N. H. 1844, xiii. p. 361. Id. Introd. B. Anst. 

 1848, p. 115. 



Jiabi'ui. — "North Pacific." 



Of this species, which is autoptically unknown to me, Mr. Gould says : "It 

 ditfers from every other that has come under my notice in the peculiar swollen 

 and raised form of the upper mandible, which moreover rises high upon the 

 forehead;" and further describes it as having the "face, ear coverts, chin, 

 abdomen, upper and under tail-coverts white: the remainder of the plumage 

 very dark brown approaching on the occiput, back of the neck, and wings, to 

 black • bill yellowish horn color, becoming darker at the tip and at the base : 

 feet in the specimen dark brown, but doubtless of a bluish gray, inclining to 

 flesh color, in the living bird. Total leng'h 30 inches ; bill 4 ; wing 21 ; tail 7 ; 



This supposed species ie by Mr. G. R. Gray placed as a synonym of nigripes 

 Audubon. The dimensions and description in general accord well ; and cer- 

 tain points of difiference of coloration may be dependant upon age. It is not 

 impossible X\\fiX, gibhosa \s based upon the fully adult nigripes, in a plumage 

 unknown until described by Mr. Gould. But comparisons of specimens are 



[May, 



