SOMATERIA. 611 



Genus SOMATERIA. 



The Eider Ducks were included by Linnreus and Brisson in the genus 

 Aiuis; but in 1822 Boie, in the 'Isis^ (p. 564), and Fleming, in his ' Phi- 

 losophy of Zoology ' (ii. p. 260), separated them under the generic title of 

 Somateria, a name for which the latter writer acknowledges his indebted- 

 ness to Leach. The Eider Duck, the Anas molUssima of Linnseus, has been, 

 by common consent, accepted as the type. 



The Eider Ducks are excellent divers, and the hind toe is furnished with 

 a well-developed membrane. They vary so much in the shape of the bill, 

 that it is difficult to find any important point in which they agree among 

 themselves and differ from their allies, except in the circumstance that 

 some part of the head is always coloured emerald-green. 



There are only five species of Eider Ducks, which are confined to the 

 northern coasts of both hemispheres. Though they form a very small 

 genus, they are easily recognizable by the peculiarities of their coloration. 

 The adult males may be diagnosed as follows : — 



Steller's Duck *. 



King Eider ]/^ black stripe on each side of the 



f Pacific Eider . . \ *^™^*' meeting at the chin. 



Scapulars and innermost secon- , _ ^ 



^ . . <; Eider Duck. 



daries entirely white i 



!^ Spectacled Eider. Breast black. 



Sharpe and Dresser, and Baird, Brewer, and Ridgway admit a sixth 

 species, the American form of our Common Eider. The former writers 

 only recognize one genus, but the latter subdivide the Eiders into three , 

 genera. With a wrong-headedness which it is not easy to understand, Baird, 

 Brewer, and Ridgway are conservative where they ought to be revolu- 

 tionary, and revolutionary where they ought to be conservative. They 

 cling to the old-fashioned notion that the form of the bill is a structural 

 character and of generic value, and thus complicate the science of orni- 

 thology by an unnecessary multiplication of genera, whilst in their nomen- 

 clature they adopt the new-fashioned practice of attem23ting to carry out 



* The Pied Duck (Fulif/ida lahradoria) has been included by some ornithologists in the 

 genus Somateria, and is somewhat intermediate between the Long-tailed Duck and 

 Steller's Duck, thus connecting the two genera ; but, on the Avhole, its alHnities appear to 

 be more with the former genus. 



