EUROPEAN GULLS. 
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4 Silvery bluish gray gull. L. argentatoides, Brehm. 
5 Small silvery gull. L. argentaceus, Brehm. 
6 North American silvery gull. L. Americauus, Brehm. 
Second Division. 
White winged darting gulls. Laroidse leucopteroi. 
1 Great white winged darting gull. L. glaucoides, Brehm. 
2 Middle sized white winged darting gull. L. leucopteros, Brehm. 
3 High crowned white winged darting gull. L. sub-leucopteros, Brehm. 
Third Division. 
Herring gulls. Laroidse harengorum. 
1 Great herring gull. L. melanotos, Brehm. 
2 Small-billed herring gull. L. harengorum, Brehm. 
3 Thick-billed herring gull. L. fuseus, Brehm. 
Fourth Division. 
Storm gulls. Laroidse procellosi. 
1 Pomarine storm gull. L. procellosus, Brehm. 
2 Northern storm gull. L. cnnus, Brehm. 
3 High crowned storm gull. L. canescens, Brehm. 
Fifth Division. 
Three-toed gulls. Laroidse tridactyli. 
1 Great three- toed gull. L. tridactylus. 
2 Greenland three-toed gull. L. rissa, Brehm. 
3 Small three-toed gull. L. minor, Brehm. 
GiiNUS IV. 
Swallow gull. Xema. — Leach and Boje. 
1 Black-headed swallow gull. X. melanocephalon, Boje. 
2 Lead gray-headed swallow gull. X. caniceps, Brehm. 
3 Laughing swallow gull. X. ridibundum, Boje. 
4 Capped swallow gull. X. pileatum, Brehm. 
5 Capucin swallow gull. X. capistratrum, Boje. 
6 Small swallow gull. X. minutum, Boje. 
Genus V. 
Ivory gull. Gavia. — Brisson and Boje. 
1 Great ivory gull. G. eburnea, Brehm. 
2 Small ivory gull. G. uivea, Brehm. 
Genus VI. 
Rapacious sea swallow. Sylochelidon : — Brehm. 
1 Baltic rapacious sea swallow. S. Balthica, Brehm. 
2 Schilling's rap. sea swallow. S. Schillingii, Boje. 
3 Caspian rap. sea swallow. S. Caspia, Brehm. 
Genus VII. 
Laughing sea swallow. Geloclielidon. — Brelim. 
1 Baltic laughing sea swallow. G. Balthica, Brehm. 
2 So uthern la ugning sea swallow. G. meridionaus, Brehm. 
3 Land laughing sea swallow. G. agruria, Brehm. 
