1880.] 



SPECIES OF ANATIDiE. 



533 



Table II. Distribution of the Anatidse. 



I will make a few observations on each of these five categories. 



I. Arctic Anatid.e. 



The Arctic Anatidae are, as will be seen, by far the most nume- 

 rous, these birds with their thick covering of feathers and aquatic 

 habits being more naturally adapted to cold and watery chmates. 

 Out of the 33 known species of Geese 20, out of the' 10 known 

 Swans 7, and of the 31 Sea-Ducks not less than 26 belong to this 

 category. Of the whole number of 1/6 generally recognized species 

 of Anatidse, 77 may, I think, be best set down as Arctic — although 

 some of them, such as Tadorna rutila, Fuligula rufina, and Marmaro- 

 netta angustirostris, cannot be strictly so termed, as they inhabit only 

 the temperate portions of the Palaearctic Region. Very many of tlie 

 Palaearctic species also, as will be noted below, go far south in winter, 

 and intrude far into the ^Ethiopian, Indian, and Neotropical Regions. 



The generic forms restricted to the Arctic area are not numerous, 

 except among the Fuliguliii*, where out of 1 1 known genera (as will 

 be seen by the subjoined Table), 8 are not met with elsewhere. 

 Amongst the Anatinse, Aix only is peculiarly Arctic. 



Table III. Distribution o/FuligulinEe. 



' Certain species of Anatinie occur in more than one of the regions; so that 

 the total of species is in this case less than the sum of its constituents. 



35* 



