BIRDS ANSERINAE. 



Liit of specimens. 



759 



Sub-Family ANSERINAE. 



As already stated, the chief characters of the Anserinae are to he found iu the elevated body, 

 with the lengthened tibia and tarsus, fitting the species for a terrestrial life. They walk about 

 much more than the other Anatidae, although equally able to swim. Their necks are shorter 

 than those of the swans, but decidedly longer than in the ducks. 



A common character, at least in most genera, is seen in the plates on the anterior portion of 

 the tarsus, which, as in the swans, are small and hexagonal, becoming smaller behind. In the 

 true ducks, the front of the tarsus is covered with transverse scutellae, the sides and behind, 

 however, are reticulated. 



The bill is generally rather short, and higher than broad at the base, in this differing from 

 most ducks ; it also tapers in most cases quite rapidly to the tip, which is constituted entirely 

 by a large convex decurved nail. Tlie foramen of the bill, in which the nostrils open, is very 

 large, though mostly occupied by membrane. The tarsus is generally longer than the com- 

 mi.ssure or the middle toe without its claw. The cheeks are densely feathered to the bill. 



The plumage is never very brilliant, white, black, and gray predominating. As in the 

 swans, both sexes are colored alike, in this differing from the other Anatidae. 



I difier from most authors in placing Dendrocygna in the present sub-family, rather than 

 with the Anatinae. Its characters are, indeed, so peculiar as almost to warrant its forming the 

 type of a separate sub-family. In the elevated base of the bill, with the large nail at the 

 extremity, and the lengthened legs, with the hexagonal scales in front of the tarsus, there is 

 certainly a much closer relationship to the geese than to the ducks. ^ 



The North American genera of the Auserinae, as defined chiefly by Keyserling and Blasins, 

 are as follows : 



Ansereae. — Bill tapering to the tip ; as long as the head. Nostrils reaching about to the 

 middle of the commissure. Tibia bare near the lower end only. 



Anser. — Bill as long as the head ; mostly red or orange colored. The lamellae of upper 

 mandible project below the edge as conical points. Nostrils opening behind the 

 middle of the commissure, the anterior edge only reaching to this point. Tip of 

 hind toe reaching the ground. 

 Bernicla. — Bill shorter than the head ; black. Lamellae of upper jaw hidden by the 

 margin of bill. Nasal apertures lying over the middle of the commissure, their 

 anterior edge reaching beyond this point. Hind toe elevated ; rudimentary ; not 

 touching the ground. 



* Bonaparte, indeed, in bia last schedule of Anatidae, Comptee Rendus, XLIII, September, 1S56, places Dendrocygna with 

 Tadorna, Chemlopez, &c, in a section Tadorneae of I'UctropUridae. 



