268 INniAN DUCKS. 



Geuus MERGANSER. 



The differences between Aferuanser and Mo'ijiis liave already ))eeu 

 defined, and there is no other oenus found, or likely to be found, in India 

 with which it can possibly be associated. 



According to Salvadori, there are seven species in the genus, but he 

 <{[\idef^ Mer(/aHse7' castor into two species, and the Indian form he designates 

 Merganser comafiis, and distinguishes as being " somewhat smaller, the 

 feathers of the crest thinner, narrower, and longer; the bill usually shorter; 

 the male has the black edges of the terlials broader, the lower back and 

 rump paler grey and usually much freckled with white." I have had 

 very large series of Mergansers pass through my hands now, and, as 

 regards these differences, both forms vary infer se in every respect, and 

 I cannot understand how they can be made specific, so, in this case, I have 

 suppressed Merganser comatus, and think our birds should be known as 

 castor, together with the European form. 



No simpler key to the two Indian species can be found than Blanford*s, 

 which I give below : — 



it. Head and upper neck black glossed with green. (Adult males.) 



a'. Lower parts white throughout M. castor. 



h'. Upper breast rufous with black marks M. serrator. 



h. Head and upper neck rufous. (Females and uon-adult males.) 



c. Chin wliite, back grey M. castor. 



d'. Chin streaked with rufous, back brown M. serrator. 



