CYGXCTS. 413 



. Cervical vertebrae 23 to 25 ; neck as long as 



body or longer Cygnince, p. 413. 



b. Cervical vertebras less than 20 ; neck shorter 



than body. 

 a'. Bill depressed and flattened towards the 



tip. 



a". Trachea of male not inflated into a 

 bulba ossea ; legs adapted to walking ; 

 sexes generally alike ; plumage as a 



rule grey or brown Anserince^pAlo. 



b". Trachea of male inflated at base into a 

 bulba ossea (see p. 421) ; legs modified 

 for swimming : sexes as a rule dis- 

 similar Anatince, p. 420. 



6'. Bill not depressed, slender, hooked at 



end Mergince, p. 46 7. 



The brief account of the habits are chiefly taken from Hume's 

 descriptions in ' The Game Birds of India, Burma, and Ceylon.' 

 I can in many cases testify to the accuracy of Hume's account 

 from my own observations. 



Subfamily CYGNIN^E. 



Neck very long, as long as the body or longer ; cervical vertebras 

 23 to 25. Size large. Sexes alike. Hind toe not lobed. 



Genus CYGNUS, Bechstein, 1803. 



Bill of moderate size, raised at the base, of nearly equal breadth 

 throughout ; nostrils elliptical, about halfway down the bill ; lores 

 naked ; wing long ; tail short, well rounded at the end ; legs short, 

 stout, placed far back. 



Swans are found in the temperate and subarctic portions of the 

 Northern hemisphere, in South America, and Australia. Two 

 species have been obtained, as rare stragglers, within Indian limits. 



Key to tlie Species. 



Culmen with a prominent knob at the base in adults ; 



loral space black C. olor, p. 413. 



No knob at base of bill : loral space yellow C. musicus, p. 414. 



1577. Cygnus olor. The Mute Swan. 



Anas olor, Gmel. Syst. Nat. i, 2, p. 501 (1788). 



Cygnus olor, VieilL Nouv. Diet. d'Hist. Nat. ix, p. 37 ; Blanf. S. F. 



vii, p. 99 ; id. P. A. S. B. 1878, p. 138 ; Hume, S. F. vii, p. 101 ; 



id. Cat. no. 944 ter ; Hume Sf Marsh. Game B. iii, p. 41, pi. ; 



Barnes, Birds Bom. p. 394 ; Salvadori, Cat. B. M. xxvii, p. 35 ; 



Baker, Jour. Bom. N. H. Soc. xi, p. 16. 



