(syn. Mergellus Ϯ Smew M.albellus) L. mergus type of waterbird < mergere to plunge in; anas, anatis duck; "All the birds of this family were included by Linnæus in his genus Mergus, to which we usually give the name of Merganser. Of the four species that inhabit Europe and North America, one, Mergus Albellus, differs from the rest in having the bill so much shorter and broader as to resemble that of a Duck, while its marginal lamellæ are oblique, and not pointed as in the larger species ... Now, the Linnæan generic name, Mergus, ought to be continued with the larger, more conspicuous, and best known species: thus, Mergus Merganser and Mergus Serrator. But as Brisson, a contemporary of Linnæus, named the same genus Merganser, it has been thought more expedient to make that the generic name of the larger species, and employ the Linnæan name, Mergus, for the small species. If, on the other hand, Merganser, which signifies Diver-Goose, be applied to the large species, why should not Merganas, or Diver-Duck, be applied to the smaller? There is no consistency in the nomenclature of natural objects; but, to prevent the necessity of using a new generic name, I shall adopt those of Merganser and Mergus already used" (MacGillivray 1852).