XXI 



GENUS ALCA. 

 Auk. 

 Alca Torda Razor-billed Auk 



GENUS MERGULUS. 



Sea Dove. 

 Mergulus alio Common Sea Dove 



GENUS URIA. 

 Guillemot. 

 Uria troile ' Foolish Guillemot 



" gryllrf Black 



FAMILY COLYMBIN^. 

 DIVERS AND GREBES. 



GENUS COLYMBUS. 

 Diver. 

 Coiymbus glacialis Great Northern Diver 



" sepientrionalis Red-throated •• 



GENUS PODICEPS. 

 Grebe. 

 Podiceps cornutus Horned Grebe 



" Carolinensis Pied bill " 



" cristatus Crested " 



" rubricoUia Red-necked " 



