856 U. S. p. R. K. EXP. AND SURVEYS — ZOOLOGY — GENERAL REPORT, 



Plumage entirely white ; bill bright yellow, dusky at the base ; tarsi moderate. 



P. ebumeus. 



Plumage more purely white than in the above species ; bill short, yellow, with the 



point orange; tarsi short P. hrachytarsi. 



PAGOPHILA EBURNEA, Kaup. 



The Ivory Gnll. 



Lams eburneKS, Gmel. Syst. Nat. I, 1788, 596.— Bonap. Syn. 1828, No. 297.— Rich. & Sw. F. B. A. II, 1831, 419.— 



NuTT. Man. II, 1834, 301.— Aud. Birds Am. VII, 1844, 150 ; pi. cccc.\lv. 

 Pagophiltt eburnea, " Kaup," Eruch, Cab. Jour. 1855, 286.— Ron. Cons. Av. II, 1856, 230. 

 Larus candidus, Parr. Fauna Groenl. 67. 

 Gallia nivea, Brehm. 



Sp. Ch.— Mull. The entire plumage is pure white ; bill bright yellow, dusky at the base ; margins of the eyelids vermilion ; 

 iris brown ; legs and feet blaclc. Length about 19 inches ; wing, ISj ; tail, 6^ ; bill, 1 5-12 ; tarsus, 1 7-12. 

 Httb. — Coasts of Arctic America, Labrador, Newfoundland. 



There are no specimens of this species in the oollection. 



In the cabinet of my friend J. P. Giraud, jr., esq., are two fine specimens, which originally 

 belonged to Mr. Audubon. 



PAGOPHILA BEAOHYTARSI, Hollboll. 



TUe Sliort-leggecl Gull. 



" Pagophila brachylarsi, Hollb." Bruch, Rev. Lar. in Cab. J. 1855, 287. 

 " Pagophila niveus, Brehm," Bonap. Cons. Av. II, 1856, 230. 



Bruch says of this species, ".resembles P. eburnea in all its parts, but is smaller ; the wings 

 extend two lines beyond the tail." 



Bonaparte makes it identical with L. niveus, Brehm., to which he gives precedence, and 

 describes it as similar to P. eburnea, but whiter and handsomer ; as being larger than that 

 species, and having a shorter bill, which is yellow, with the point orange. 



Hab. — Greenland. 



There are no specimens in the collection. 



RHODOSTETHIA, Macgillivray. 



lihodoslelhia, Macgill. Man. of Orn. II, 1842. 



Cn. — Bill short and slender; upper mandible straight for half its length, then slightly curved to the tip, which is very narrow ; 

 prominence on the lower mandible small ; wings long and pointed ; tail wedge-shaped ; tarsi rather strong ; toes united by a 

 Mill web, hind small and elevated. 



But a single species in this genus, found in the Arctic regions; its most striking characteristic 

 is the cuneate form of the tail. 



RHODOSTETHIA ROSEA, Bonap. 



The Wedge-tailed Gull. 



Larus roseus, Jard. & Sei.bt, Ills, of Orn. , pi. x\v, 



295.— Aud. Birds Am. VII, 1844, 130. 

 lihodostethia rosea, Bruch, Cab. Jour. 1855, 278.— Bon. Cons Av. 11, 1856, 230. 

 Laiits rossii, Rich. Parry 2d Voy. App. 1825, 359.— Rich. & Sw. F. B A. II, 1831, 427.— Nutt. Man. II, 1834, 



