of the United States. 381 



equal to the middle toe, not extremely compressed ; tibia 

 smooth ; toes moderate, middle longest, inner shortest ; webs 

 full, entire, but not very large ; hind toe equal to a phalanx 

 of the middle, simple, touching the ground at tip. Wings 

 moderate, acute; primaries elongated, first and second, or 

 second only, longest. Tail of from fourteen to twenty 

 feathers. 



Female very different from the male in full plumage. 

 Young generally more or less resembling the female. Moult 

 twice in the year, the female partially, the male completely, 

 assuming in summer the humble dress of the female. Plu- 

 mage thicker than in the Geese, but not so thick as in the 

 Swans and Fuligula?. A mirror or speculum on the wing in 

 most species. Colors of the female dull, grayish. Trachea 

 swelling at the bifurcation into cartilaginous capsules. 



Migrate in large flocks : in autumn and winter keep in fresh 

 water and rivers, affecting green shores and sedgy places, es- 

 pecially shallow water, where they can reach the bottom with 

 their bill, without diving. Somewhat nocturnal : feed and 

 travel by night. Food chiefly vegetable, plants and seeds, 

 but also aquatic animals. Disposed to polygamy : build in 

 the grass, more or less near water, some in hollow trees: 

 nest lined with down : eggs numerous. Female alone incu- 

 bates, without any assistance from the male, and covers the 

 eggs with the lining of the nest and other materials when 

 obliged to leave them. The male does not trouble himself 

 about the young. Walk comparatively well, but not so well 

 as the Geese, with the body poised, and the feet close 

 together. While swimming raise the tail and stretch their 

 body. Avoid deep water : dive only when compelled by 

 necessity, or in the breeding season. Flight comparatively 

 light, often high, whistling. 



Spread all over the globe : species numerous, more so in 

 temperate regions. We divide them into four subgenera, two 

 only of which are found in the United States. 



Vol. II. 48 



