288 WATER FOWL. 



years ago, is now extinct. It was remarkable for the unusual 

 structure of the bill, which differs from all those of living species 

 of Ducks, and for its striking black and white plumage. It was 

 a strong flyer, and apparently perfectly competent to take care 

 of itself, and the cause of its disappearance from our Continent is 

 an unfathomable mystery. Many theories have been advanced to 

 account for its extinction, but, as none admit of proof, it is impos- 

 sible to arrive at a satisfactory explanation. 



GENUS CLANG ULA 

 (Latin clangula, dim. of clangor, a noise). 



Clangula. Leach in Ross, Voy. Disc, App., 1819, p. xlviii. 

 Type Anas clangula, Linn. 



Bill shorter than head, high at base and tapering to tip. Nail 

 prominent and hooked. Anterior end of nostril nearer to the tip 

 than to the loral feathers. Tail rounded, of sixteen feathers. 



Two species of this genus are found in North America, both of 

 which are also natives of parts of the Eastern Hemisphere. The 

 Common Golden Eye of our coasts and rivers, while in plumage 

 it resembles in every particular the bird obtained in the Old 

 World, has been separated as a distinct race, on account of 

 being slightly larger on the average. A species or a race 

 founded solely upon the slight, constantly varying size of indi- 

 viduals has a very difEcult position to maintain in any family 

 of birds, but is of a still more uncertain quantity when the 

 establishment of so important a distinction is attempted in a 

 like manner with members of the Anatid^, as they notori- 

 ously vary in size, so that individuals of the same species can be 

 readily found whose measurements differ at times in a surprising 

 degree. It is only necessary to look at the measurements of a 

 series of almost any species of the Anatidse to see how wide 

 apart the two extremes are, and within the range some exam- 

 ples would undoubtedly be found agreeing exactly with their 

 foreign relatives, if they had any. It seems as if ornithologists 

 acted at times under the conviction that, because a species is 

 found in North America!^ it must be specifically or racially differ- 

 ent from its Old- World representatives, and then the slightest 

 variation is deemed sufficient to bestow upon it a new name. 

 There are a number of such instances among the Anatid*, 



