ANATID^. — LX. 139 



TMih. Ducks with none of the above peculiarities. 



i. Upper mandible gibbous at its unfeathered base; black 

 or brown. (Edemia, 19. 



a. Upper mandible not gibbous where unfeathered. 



j. Nail at tip of bill narrow and distinct. 



^. Head black or brown; nostrils sub -basal; bill 

 longer than tarsus. . . . Fulix, 12. 



M'. Head reddish or brownish, without white ; nos- 

 trils nearly median ; bill longer than tarsus. 



Aythya, 13. 



kkk. Head black or gray, with white ; nostrils nearly 

 median ; bill about as long as tarsus. 



Clangula, 14, 

 jj. Nail broad, scarcely distinct. 



I. Feathers extending on culmen- and partly on sides 



of upper mandible. . . Somateria, 18. 



II. Feathers not extending on culmen; bill small, 



much tapering. . . Histrionicus, 17. 



ff Bill narrow, nearly cylindrical; the lamellae acute, recurved, 

 like saw-teeth; usually crested. Fish Ducks. (Mergin.e.) 



m. Bill not black ; tareus more than half the length of middle 

 toe Mergus, 21. 



mm. Bill black; tarsus half length of middle toe. 



Lophodytes, 22. 



/. CYGNUS, Linnagus. Swans. 

 > 0/or, Wagler. 



1. C. buccinator, Rich. Trumpeter Swan. Tail 

 (normally) 24 feathered; bill without yellow spot, longer 

 than head; nostrils sub -basal; L. about 50. Miss. 

 Valley, W. and N. 



2. C. columbianus, (Ord.) Coues. Whistling Swan. 

 Tail 20 feathered; bill with a yellow spot, not longer 

 than head; nostrils median; L. 50. N.Am. {C.ameri- 

 canus^ Sharpless.) 



