Diagnoses of Families and Genera 569 



the length of the culmen, not feathered as far as the nostrils, the edges 

 of the maxilla bent over the mandible. Nail very large and broad, 

 forming tip of bill, not hooked. Nostrils near base and high on max- 

 illa. Speculum violet. One species in genus, a bird of the far North. 



Arctonetta. Bill shorter than head, tapering from base to tip, not 

 swollen, and without prolongations on forehead, feathered on the cul- 

 men beyond the nostrils, this feathering sweeping backward in an 

 oblique line from culmen to mouth. Nail as in Eniconetta. No specu- 

 lum. Eyes surrounded by an elevated space of short, velvety feathers. 

 One species in genus, found in Bering Sea. 



Somateria. Bill about half as long as head, much swollen, with 

 prolongations stretching far back on forehead, feathering extending 

 well forward on culmen and on sides toward nostrils. Nail large and 

 broad, hooked and forming tip of bill. No speculum. Tertiaries 

 curving downward over wing. Male black and white, female brown. 

 Four species are found in North America, two confined to the North 

 Atlantic, one to Bering Sea, and the fourth a bird of the far North. 



Oidemia. Bill much swollen at base, depressed at tip, with no pro- 

 longations on forehead. Large, hooked nail forms entire tip of bill. 

 Nostrils usually in front of the middle of bill. Feathering extending 

 farther on culmen than on lores. No speculum. Male black, female 

 dusky. Bills of males brightly colored. Four species occur in North 

 America, but one only as a straggler, and all breed in northern lati- 

 tudes. 



Erismatura. Bill about as long as head, very broad, almost as 

 broad as high at base, and widened and depressed at end. Tail 

 feathers very stiff, narrow, and pointed, with the shafts grooved on the 

 lower side. Tail-coverts very short. Nail of bill very narrow at first, 

 then widening, and curved in a hook over the mandible. One species 

 is found in North America. 



Nomonyx. Similar to Erismatura ; but bill rather more narrow, 

 with the nail large and broad and not bent downward in a hook over 

 mandible. Inner secondaries long, folding over primaries. Only one 

 species in genus, a native of tropical America. 

 Subfamily Anserinas. The Geese. Type : Neck somewhat shorter 

 than body. Tarsus longer than middle toe without claw. Bill usually 

 short, high and compressed at base, and tapering to rather narrow tip, 

 which has * broad nail. Lamellae present on mandible. Lores 

 feathered. Tarsus with small, irregular plates in front. Hind toe 

 without a lobe. Sexes alike. Wing rarely with metallic speculum ; 

 no speculum in North American species. 



