566 The Water-fowl Family 



short and blunt, not pointing backward. Crest of male large and 

 semicircular. Tarsus about half as long as middle toe with claw. 

 Tail more than half as long as wing. Bill black. One species in 

 genus, confined to North America. 



Mergus. Length of bill about twice its depth at base. Bill shorter 

 than head, also shorter than tarsus, with the serrations on mandibles 

 as in Lophodytes, but smaller and more numerous. Crest as in Lopho- 

 dytes, but smaller. Bill blackish. One species in genus, a native of 

 the eastern hemisphere; accidental in North America. 

 Subfamily Anatinas : The River-ducks. Type : Neck shorter than 

 body. Tarsus shorter than middle toe, without claw. Bill broad, 

 flattened, with toothlike nail ; the lower mandible with a series of 

 lamellae on sides and on cutting edge. Lores feathered. Tarsus with 

 transverse scales in front. Hind toe without a lobe. Sexes unlike. 

 Wing usually with metallic speculum. 



This subfamily contains in North America nine genera, one of 

 which only occurs as a straggler in Greenland, and sixteen species 

 and subspecies. The males are birds of striking plumage, with usu- 

 ally a metallic patch of feathers on the wing; the females much 

 plainer. They frequent chiefly fresh water, live largely on vegetable 

 food, and have, consequently, flesh of fine flavor. Most species nest 

 on the ground. 



Generic Types. Anas. Bill about as long as head, broad, sides almost 

 parallel, slightly widening toward tip. Culmen depressed in centre, 

 rising toward base and tip. Lamellae of bill scarcely exposed. Specu- 

 lum brilliant. Tail rounded, of pointed feathers. Three species and 

 two subspecies found in North America. 



Chaulelasmus. Bill somewhat shorter than head, rather narrow, 

 the sides parallel. Culmen slightly depressed in centre, level toward 

 base and tip. Lamellae of bill plainly exposed. Speculum dull. Tail 

 short and rounded, of pointed feathers. One species in genus, al- 

 most cosmopolitan. 



Mareca. Bill as in Chaulelasmus, but rising somewhat toward base. 

 Lamellae only slightly exposed. Speculum of male bright. Tail pointed. 

 Two species are found in North America, one only as a straggler (?). 



Nettion. Size very small. Bill shorter than head, very narrow, 

 sides almost parallel. Culmen straight in terminal two-thirds, rising 

 at base. Breadth of nail about one-fifth breadth tip of bill. The 

 lamellae completely concealed. Speculum green ; no blue on wing. 

 Nape with a small crest. Two species of this genus are found in North 

 America, one only as a straggler. 



