MERGANSER. 193 



in autumn only, and the colours of the males undergo an 

 extraordinary amount of change towards mid-summer from an altera- 

 tion in the colour of the feathers themselves. They do not acquire 

 their full plumage till the second autumnal moult. They are excel- 

 lent divers, using their wings as well as their feet ; and they live 

 chiefly on fish. The tongue is long, pointed and ciliated ; the 

 gizzard is less muscular, and their intestines shorter than those of 

 the ducks. They possess two cseca of moderate length. The 

 labyrinth or the lower part of the trachea of the males is enormous, 

 and partly membranous. Only five or six species are known. Of 

 these, two visit India in winter ; one found in rivers in the Hima- 

 layas ; the other spread sparingly through Northern India. 



Gen. Mergus, Linn. 



Char.— Those of the family. 



The following species is separated by Bonaparte as Merganser :■ — 



29. Mergus castor, Linnaeus. 



Blyth, Cat. 1798 — M. merganser, Linn. — M. orientalis, 

 Gould — Gould, Birds of Europe, pi. 384. 



The Merganser. 



Descr. — Male, head (with a short thick crest,) and upper part of 

 the neck, glossy blackish-green; lower part of the neck white ; 

 upper back and scapulars next the body, deep black ; the rest of 

 the back and upper tail-coverts ashy, the tips of the feathers 

 whitish here and there ; tail ashy-grey ; breast, abdomen, and under 

 tail-coverts white, tinged with orange-buff ; wing-coverts and 

 outermost scapulars rich buff-orange, and the latter edged with 

 black. 



Bill deep blood-red, black on the culmen, paler at the edges ; 

 irides red ; feet orange-red. Length 26 inches ; wing 11 ; bill 

 at front 1\ ; tarsus 2. 



The female (and young males till the second moult,) have the 

 head and neck reddish-brown ; the throat white ; the upper plumage 

 ashy ; beneath yellowish-white, the sides of the breast and the 

 flanks pale ashy; a white speculum; primaries black; tail ashy- 

 brown. 



2 6 



