LON GIPEKNES, 
FAMILY I.— LA RID IS. 
SUB-FAMILY LAKIJLE. 
GENUS LARUS. 
Larus. Linn. Syst. Nat. (1735.) 
69. 
LARUS CALIFORNICUS. ) 
70. 
— OCCIDENTALIS. J 
Yol. 
II. 
Plate 
LII. 
71. 
— BRACHYRHYNCUS. 1 
72. 
— HUTCHINSII. j 
Vol. 
II. 
Plate 
LIH. 
73. 
GLAUCESCENS. 
The Glaucus Gulls resemble each other in many particulars, and one might be excused if the supposition should occur, that they 
but presented different stages of ftlumage of the same species. Thus we have the L. Hutchinsii, which is pure white, succeeded 
by L. Glaucus, also white, with a mantle of the lightest possible blue; then L. Leucopterus, pearly blue -on mantle and primaries, 
the latter tipped with white ; this followed by L. Chalcopterus, which resembles the previous species, but has the wings of L. Glaucescens, 
which has a pearl-blue mantle and blackish primaries, spotted and tipped with white. Slight variations between these different forms 
would easily establish an unbroken chain from the white L. Hutchinsii to the dark L. Glaucescens. 
As the principal differences between L. Glaucescens and L. Glaucus consist in the primaries and dark mantle of the former, it did 
not seem necessary to devote a plate to represent it, and therefore I give illustrations of the primaries of the natural size of the 
two species for comparison. The specimen of L. Glaucescens came from Puget sound, and was numbered 27,084. I am indebted 
to the Secretaries of the Smithsonian Institution for the loan of the example to be figured in this work. 
LARUS olaucksckns. 
LAI1US GLAUCUS. 
74. LARUS BOREALIS— L. ARGUN TATES. 
Larus Borealis. Brandt. Mus. Petropolit, Bruch. Monogr. 
Lak. in Journal fur Ornith. (1853). p. 101. sp. 19. 
This is the Herring Gull of the West coast, and judging from the specimens I have been able to examine, I should consider it to be 
identical with the Larus Argentatus of the Eastern shores of the continent. 
GENUS RISSA. 
Rissa. Leach. Steph. Gen. Zool. Vol. XIII. (1825.) p. 180. 
75. RISSA KOTZEBUI. ] 
76. — NIYEA. j 
Yol. II. Plate LIY. 
SUB-FAMILY LESTRIDINiE. 
GENUS STERCORARIUS. 
Stercorarius. Ilriss. Orn. (1760). Vol. VI. p. 149. 
77. STERCORARIUS CATARRACTES. Yol. II. Plate LY, 
SUB-FAMILY STERNINJS. 
78. THALASSEUS CASPIUS. 
GENUS THALASSEUS. 
Thalasseus. Boie. Isis. 1822. p. 563. 
Yol. II. Plate LYI. 
