50 ZOOLOGY OF THE VOYAGE OF THE SULPHUR. 



Family— PROCELLARIDiE. 



Thalassidroma furcata. 



Plate XXXIII. 



Procellaria furcata, Lath. Ind. Om. vol. ii. p.. 825. Gmel. edit. Linn. vol. i. p. 501. 



Fork-tailed Petrel, Lath. Gen. Syn. vol. vi. p. 410. Penn. Arct. Zool. vol. ii. No. 463. Lath. 

 Gen. Hist. vol. x. p. 188. 



Throat greyish white ; all the upper and under surface shining silvery grey ; wings dark slate 

 grey, passing into silvery grey on the greater coverts ; tail forked and grey, gradually 

 deepening towards the tip ; external web of the outer feather on each side white ; under 

 tail-coverts white ; bill black ; feet brown. 



Total length, 8 inches; bill, § : wing, 6 ; tail, 3 J ; tarsi, §. 



Inhab. Sitka, Russian America. 



The figures are of the natural size. 



Family— LARID^. 

 Larus brachyrhynchus. Gould. 



Plate XXXIV. 

 Larus brachyrhynchus, Gould, in Froc. of Zool. Soc., July 25, 1843. 



Spec. char. Lar. capite, collo, corpore inferiore, uropygio crissoque albis ; dorso 



alisque cinereis ; remige primo, ad pagonium externum et ad apicem ; remigibusque 



sequcntibus tribus, ad apicem, nigris ; remigibus secundo, tertio et quarto, notd 

 cinered terminali ; quinto vittd nigra et apice cinereo. 



Head, neck, all the under surface, rump, upper and under tail-coverts, and tail, pure white ;. 

 back and wings, including the primaries, grey, passing into white at the tips of the sca- 

 pularies, secondaries, and all but the first five primaries, which are thus marked : — the 

 outer primary has its external web, and three inches of the tip of the inner web deep 

 black ; the next primary is tipped with black for three inches and a half on its outer, 

 and two inches and a half on its inner web, and has a very minute speck of grey at the 

 extreme tip ; the third primary is tipped with black for two inches, and has a small spot 

 of grey at the extremity ; the fourth is tipped with black for an inch and a quarter, and 

 has a larger spot of grey at the extremity than the third ; and the fifth is crossed by an 

 irregular band of black near the tip three-quarters of an inch wide, the extremity being 

 grey, fading into white on the margin of the inner web ; bill primrose yellow ; feet orange 

 yellow. 



Total length, 14 inches; bill, 1J; wing, \2\; tail, 5£ ; tarsi, 1£. 



Inhab. Russian America. 



The figure is about one-third of the natural size. 



