INTRODUCTION. 
CXXIX 
351. Harelda glacialis ........... Vol. V, PI. XXXIII. 
Long-tailed Duck. 
A common winter visitant ; arrives in the Scottish firths in great abundance during the months of 
autumn. 
Subfamily MERGING:. 
The Mergansers are a very distinct family, differing in structure and mode of life from the Ducks or 
Cormorants, to which otherwise they are nearly allied. They live on the waters of both the Old and the 
New World, and consist of about ten species. 
Genus Mergus. 
352. Merges castor ........... Vol. V. PI. XXXIV. 
Goosander. 
A winter bird, frequenting our lakes when they are not frozen over; very destructive to freshwater fish. 
Always to be seen at Clumber in autumn and winter, goes north in summer. 
353. Mergus serrator ........... Vol. V. PI. XXXV. 
Merganser. 
Found in Britain at all seasons ; common in the north of Scotland. 
354. Merges cucullatus .......... Vol. V. PI. XXXVI. 
Hooded Merganser. 
An American species, which has occasionally been found in Europe and Britain. 
355. Merges albellus . . . . . . • . . • . Vol. V. PI. XXXVII. 
Smew or Nun. 
A winter bird, rather scarce. Breeds in Lapland and the adjoining countries. 
Family PODICIPIDiE. 
When the birds of the world are taken in review, it is interesting to note that certain forms are restricted 
to very limited areas, while others are as widely distributed. It is to the latter category that the Grebes or 
members of this family pertain ; for my experience tends to prove that one or other of the numerous species 
are found throughout the entire globe ; even in the islands of the South Pacific they are to be met with, and 
also all over North and South America. They do not appear to be limited by elevation, but tenant the 
