FAMILY LAKID.E. GULLS AND TERNS. 



39 



Section 2. Length, over 21; bill, over 2; underparts, 



not white. 



Outer webs of primaries, ash color (immature). 



Lams glaucus. Glaucous Qull. 



See No. 24. 



Outer webs of primaries, dark brown; wing, over 17.50; depth of l)ill at angle, over .90 

 (immature). Lams mar inus. Great Black-backed Qull. 



See jSTo. 27. 



Outer webs of primaries, dark browu; depth of bill at angle, under .90; wing, under 17.50 

 (immature). Lams argentatus smithsoniamis. American Herring Qull. 



See No. 30. 



Section 3. Length, over 2 1 ; bill, under 2 ; underparts, white. 



Back, graj'isli ])ln<', more or less black on primaries. 



Lams arfjentntus smithsonUinns. American Herring Qull. 



See Xo. :\(). 



Back, pale pearl color; pri- 

 maries, whitish or pearl color, 

 shading to white at tips. 



Lams leucnpfems. 

 Iceland Qull. 

 See No. 25. 



Great Hlack backed Gull. 



Kinir liillcil (Mill. 



Back, pale jn-arl color: iiriniarif? 

 marked with slaty gray. 



Liiriis kxmlieni. Kumiien's (iull. 

 See No. 2(;. 



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HiMThi;.' (iull. 



