NATATORES. 



419 



[184.] 4. Larus eburneus. (Linn.) Ivory Gull. 



Genus, Larus, Linn. 



Ivory Gull. Penn. Arct. Zool., ii., p. 529, No. 457- 



Larus eburneus. {Ivory Gull). Sab. Greenl. Birds, p. 548, No. 21 ; Suppl. Parry's First 



Voy., p. cciv., No. 18. 

 Mouette blanche ou senateur (L. eburneus). Temm., ii., p. 769. 

 Larus eburneus. Bonai>. Sy?i., No. 297- 



This beautiful Gull frequents Davis's Straits, Baffin's Bay, and various parts 

 of the northern shores of the American continent. We observed it breeding- in 

 great numbers on the high perforated cliffs which form the extremity of Cape 

 Parry, in latitude 70°. It attends the whale fishery to prey on blubber*. 



DESCRIPTION. 



Colour of the mature bird pure white. Bill wax-yellow at the base, ochre-yellow towards 

 the point. Orbits red. Irides brown. Legs and feet black. 



Form. — Bill rather stout, the gonys forming a distinct angle beneath ; commissure curved 

 only near the point. Wings an inch and a half longer than the even tail ; first quill longest, 

 second almost equal to it. Naked part of the thigh very short (less than half an inch 

 above the centre of the joint). Webs rather short. Hind toe and nail stout, short ; inner 

 toe short. 



An immature bird, killed at Hudson's Bay, has the region of the bill, lores, and chin, 

 blackish-grey ; a few scattered spots of blackish-brown on the wing coverts and scapulars, 

 with bars of the same on the end of the tail and tips of the quills. The bill blackish, tipped 

 with horn colour. Legs black. 











Dimensions. 















Inch. 



Lin. 



Inch. 



Lin. 





Inch. 



Lin. 



Bgt 



h, total 



18 







Length from nostrils to tip . 



n 



Length of inner toe 







10§ 



55 



of tail 



. 6 







,, of tarsus . . 1 



6* 



„ of its nail 



. 



4 



55 



of wing . 



13 







„ of middle toe . 1 



4 



„ of hind toe 







H 



55 

 55 



of bill above . 

 of bill to rictus 



. 1 



2 



3 



2 



„ of middle nail . 



5 



„ of hind nail . 



. 



2 



— R. 



* Mr. Hutchins describes a pure white Gull, which breeds on the Albany River, as larger than our Ivory Gull, 

 being twenty-seven inches and a half in length, five feet from tip to tip of the wings, and weighing two pounds. Its 

 bill and legs are flesh-coloured. It lays four white eggs on the ground ; and the young, which are blackish, do not 

 attain their full plumage until they are three years old. It feeds on fish. — Although the Ivory Gull, in common with 

 others of the genus, varies considerably in size, I have met with none which attain the magnitude of Mr. Hutchins's 

 bird, which, if it prove on examination to be distinct, deserves the name of Larus Hutchinsii. The Gull described by 

 Capt. Sabine in his Memoir on the Greenland Birds, p. 545, was probably an example of Mr. Hutchins's species. — R. 



3 H 2 



