8 EGGS OF NORTH AMERICAN BIRDS. 



probably indistinguishable from those of No. 43. Breeds on 

 coasts of Norton's Sound, Alaska. 



47. Great Black-backed Gull, Larus tnarinus. Eggs, 

 3 or 4, oval, varying from bluish M'hite to deep yellowish bi-own, 

 spotted and blotched with reddish brown and lilac, of varying 

 shades ; 2.20 + 2.95 to 2.30 + 3.00. Breeds on both coasts of 

 North Atlantic, in North America, from Bay of Fundy, north- 

 ward. The eggs are laid in June. 



48. Slaty-backed Gull, Larus schistiscif/us. Eggs, un- 

 known. Breeds in North Pacific, Herald Island, Arctic Ocean, 

 and Alaska. 



49. Western Gull, Larus occidentalis. Eggs, 2 or 3, 

 oval, dark olive brown, spotted and blotched with brown and 

 black; 1.80 + 2.70 to 2.00 + 2.90. Breeds from Southern 

 California, northward, in May. 



50. Siberian Gull, Larus affinis. Eggs, unknown. Breeds 

 in Greenland, Northern Asia, and Europe. 



51. Herring Gull, L^arus argentatus. Eggs, 3 or 4, sim- 

 ilar to those of No. 47, but smaller; 1.80 + 2.70 to 2.05 + 2.90. 

 Breeds in the northern portion of the old world, and in Cum- 

 berland Sound. 



51a. American Herring Gull, Larus argentaUis smithso- 

 nianus. Eggs, similar to those of No. 51. Breeds on Atlan- 

 tic coast of North America, from Maine, northward, early in 

 June. Nests composed of seaweeds and sticks, jilaced on cliffs, 

 on the ground, or in trees. 



52. Pallus's Gull, Larus cachmnans. Eggs, similar to 

 those of No. 51. Breeds on coasts and islands of North Pa- 

 cific and Arctic Oceans, on the ground, early in May. 



53. California Gull, Larus californicus. Eggs, similar to 

 those of No. 49. Breeds throughout Western North America. 



54. Ring-billed Gull, Larus delatoarensis. Eggs, 3 or 4, 

 oval, generally dark yellowish brown, rarely bluish, spots of 

 dark brown, often elongated into lines; 1.60 + 2.75 to 1.75 + 

 2.89. Breeds only in the Great Lakes, in Labrador, and north- 



