270 VERTEBRATES: BIRDS. 



The Genus Aythya comprises two American species. 



The Red-Head, A. americana, Bonap., of North Amer- 

 ica, is twenty and a half inches long, and the wing nine 

 and a half inches ; the head and neck for more than half 

 its length brownish red. 



The Canvas-Back, A. vallisneria, Bonap., of all North 

 America, is twenty inches long, and the wing about nine 

 and one third inches ; head and neck chestnut ; body 



Fig. 143. 



Canvas-Back, A. vallisneria, Bonaf). 



anterior to the shoulders, the lower back, rump, and tail- 

 coverts, black ; under parts white ; scapulars and inter- 

 scapulars white, finely dotted with black in transverse lines. 



The Genus Bucephala has the bill shorter than the head, 

 and the tail with sixteen feathers. 



The Golden-Eye, or Whistle- Wing, B. americana, Baird, 

 of North America, is eighteen and three quarters inches" 

 long, and the wing eight and a half inches ; the head and 

 upper neck glossy green ; a white patch before the eye. 



Barrow's Golden-Eye, B. islandica, Baird, of Northern 

 North America, is twenty-two and a half inches long, 

 and the wing nine and a half inches. 



The Butter-Ball, or Dipper, B. albeola, Baird, of North 

 America, is fifteen inches long, the wing over six and a 



