GEN. 281-291 OF KEY. 105 



550. LARUS EBURNEUS GM. 



Ivory Gull. 



551. LARTJS BELCHERI VIGORS. 



White-headed Gull 



552. LARUS TRIDACTYLUS L. 



Kittiwake Gull. 



552a. LARUS TRIDACTYLUS L., 

 var. KOTZEBUI (Bp.) Coues. 

 Pacific Kittiwake. 



553. LARUS BREVIROSTRIS (BRANDT) COUES. 



Short-hilled Kittiwake. 



554. LARUS ATRICILLA L. 



Gull. 



555. LARUS FRANKLINI RICH. 



Franklin's Rosy Gull. 



556. LARUS PHILADELPHIA (Oiu>) COUES. 



Bonaparte's Gull. 



557. RHODOSTETHIA ROSE A (MACGILL.) BP. 



Wedgre-tailed Gull. 



558. XEMA SABINEI (SAB.) BP. 



Fork-tailed Gull. 



659. XEMA FURCATUM (NEBOUX). 

 Swallow-tailed Gull. 



560. STERNA ANGLICA MONTAGU. 

 Gull-hilled Tern ; Jflarsh Tern. 



561. STERNA CASPIA PALLAS, 



var. IMPERATOR Coues. 

 Caspian Tern. 



662. STERNA REGIA GAMBEL. 

 Royal Tern. 



