294 WATER FOWL. 



term, Erionetta (Hpiov, erton, wool -|- vtrra., netta, a duck), was 

 proposed for the King Eider by Coues in 1884. 



The Eider Duck of the Old World, and the one obtained in 

 Greenland, have been separated by American ornithologists for 

 the same insufficient reasons given in similar cases of certain 

 Geese and Ducks, viz., a slight difference in size, to which in 

 this instance is added a variation in the color of the bill, " olive 

 yellowish" instead of "olive green";* a distinction, to most 

 persons, practically without a difference. These characters, upon 

 which a specific or subspecific separation of the birds is based, 

 are not apparent to the ordinary observer, and only occasionally 

 to the expert, and can hardly be deemed of sufficient importance, 

 considering how Ducks vary in size, and also the difficulty of 

 recognizing delicate distinctions of slight shades of olive, to 

 require the Greenland and European birds to assume any kind 

 of separate rank. Species or subspecies, where the individuals 

 require a pair of dividers, or a great ability on the part of the in- 

 vestigator, to recognize intimately related shades of color for their 

 maintenance, should not be permitted to obtain recognition in 

 what ought to be i-egarded as a serious scientific study, for the 

 differences are too apt to mislead, and seriously confuse and 

 discourage the conscientious student. 



KEY TO THE SPECIES. 



A. Feathers of forehead reaching about half 

 as far on bill as the loral feathers. 



a. Frontal angles on bill broad with round [ EIDER 

 ends - ) S.dresseri. 



b. Frontal angles on bill narrow with 

 pointed ends. 



a'. Without V-shaped mark on throat of } COMMON EIDER. f 



male. ) S. mollissitna. 



b'. With black V-shaped marks on throat ) PACIFIC EIDER. 



of male. ) S. v.-nigruin. 



B. Feathers of forehead reaching to posterior ) KING EIDER. 

 end of nostril. ) S. spectabilis. 



* Ridgway, Manual, 2d ed., 1896, p. jog. 



tin some male specimens a dusky V-shaped mark is seen on the throat, 

 but this is very exceptional. 



