186 SUBFAMILY ANATINM 



e'. Nail of the beak not hooked; wide, more than or about half the width of bill 

 at tip; culmen nearly straight, bill not broadening toward tip, not so deep 

 in proportion to height. 



i. Lamellae equally developed along edge of upper mandible; neck 



feathers normal Casarca. 



i.' Lamellae of upper mandible only moderately developed; anterior 

 edge of feathering on forehead convex; nuchal feathers elongated. 



Pseudotadorna. 



d'. Tail feathers usually more or less narrowed or pointed at tip. 



j. Bill not or not noticeably broadening toward tip, its depth at base much 

 less than length from forehead to nail; the nail distinctly hooked, its width 

 less than half that of the tip of beak, 

 k. Lamellae moderately developed. 



1. Wings normal but not reaching end of tail Anas. 



Y. Wings very small, useless for flight Nesonetta. 



k'. Lamellae extremely developed, wings normal Elasmonetta. 



j'. Bill decidedly spatulate. 



m. No soft membrane on sides of bill near its tip Spatula. 



m' Bill with a soft membrane on the sides toward the tip 



Malacorhynchus. 



c'. No wing speculum present, tail very short. 



n. Bill longer than head, at its base much higher than broad; culmen 



concave Siictonetta. 



n'. Bill about equal to length of head, nearly as high as broad at the base; 

 culmen not very concave Heteronetta. 



