ANATID^. LX. 139 



MM. Ducks with none of the above peculiarities. 

 i. Upper mandible gibbous at its uiifeathered base ; black 



or brown. (EDEMIA, 19. 



u. Upper mandible not gibbous where unfeathered. 

 j. Nail at tip of bill narrow and distinct. 



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

 longer than tarsus. . . . FULIX, 12. 

 kk. 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. 



BUCEPHALA, 14. 



jj. Nail broad, scarcely distinct. 



I. Feathers extending on culinen and partly on sides 



of upper mandible. . . SOMATEKIA, 18. 



II. Feathers not extending on culmen ; bill small, 



much tapering. . . HISTRIONICUS, 17. 



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



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



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



toe MERGUS, 21. 



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



LOPHODYTES, 22. 



7. CYGNUS, Linnasus. SWANS. 

 > Olor, 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.) 



