1. ciGNtrs. 25 



1. CYGNUS*. rr 



Type. 



Cv£miis, Bechst. Oi-n. Taschenb. ii. p. 404 (note) 



"(1803) C. olor. 



Olor, Wagl. Isis, 1832, p. 1234 C. musicus. 



Cvcnus, Temm. Man. (TOrti. 2nd ed. iv. p. 526 



'(1840). 

 Sthenelus, Stejneg. Pr. U.S. Nat. Mus. v. p. 185 



(1882) C. melancoryphus. 



Sthenelides, Stejneg. Kingsl. Stand. Nat. Hist. iv. 

 p. 143 (1885) ( = Sthenelus). 



Range. Northern hemisphere and Neotropical region. 



Key to the Species f. 



a. No knob at the base of the culmen : the trachea 



entering the carina sterni, which is hollow. 

 a'. Basal part of the bill and lores more or less 

 yellow. 

 a". Nearly the basal half of the bill yellow. 

 a'". Black apical portion of the biU o-ene- 

 rally does not extend above the nostrils, 

 and on the sides only reaches halfway 

 to the gape : larger, culmen 4'20 



inches musictis, p. 26. 



b'". Black apical portion of the bill extends 

 much above the nostrils and back- 

 wards to the gape : smaller, culmen 



3-80 inches beuncki, p. 29. 



h". The yellow colour of the bill confined to 

 a spot before the eyes ; culmen 3-82- 



4'20 inches columbiamts, p. 32. 



b'. No yellow colour at the base of the bill, 

 which is entirely black and very large ; 

 culmen 4"34-4'70 inches buccinator, p. 33. 



b. Culmen with a prominent knob at the base; 



the trachea not entering the carina sterni, 



which is simple. 



c'. Plumage of the adults entirely white olor, p. 35. 



d'. Head and neck black ; rest of the plumage 



white mehncoryphus, p. 39. 



* The generic name Cygnus was used by Bartram ('Travels,' p. 294, 1791) 

 for a species which was either C. columhianus or C. buccinator, both allied to 

 C. musicus. But Bartram was not a binomialist ! 



t I have not been able to identify the following species, which must remain 

 doubtful till a competent observer examines the type: — 



Ctqnus davidi. 



Cvgnus (Coscoroba) davidi, Swinh. P. Z. S. 1870, p. 4.30 (Tientsin). 

 Cvgnus davidi, Swinh. P. Z. S. 1871, p. 416 ; Eiwcs, P. Z. S. 1873, p. 6.51 ; 



'David 4- Oust. Ois. Chine, p. 494 (1877) ; Sclat. P. Z. S. laso. p. 507. 

 Cygnus (Koscoroba) davidi, David, X. Arch. Mus. Bull. vii. Cat. n. 438 



(1871). 



