ANATIDJE. 87 



of lores, and advancing quite to the 



nostril Arctonetta. (Page 108.) 



?'*. Feathering of forehead separated from that 

 of lores by the interposition of a more or 

 less extensive naked angle, or prolonga- 

 tion of naked skin of the bill. 



Somateria. (Page 108.) 



/'. Tail more than half as long as wing, much graduated, the 



feathers with narrow webs and very stiff shafts, their 



bases scarcely hidden by the short coverts. 



g^. Nail of bill very small, hardly visible from above, and 



bent abruptly backward beneath the tip of the 



upper mandible; outer toe longer than middle. 



Erismatura. (Page 113.) 

 g^. Nail of bill normal (i.e. large, almost Avholly visible 

 from above, and not bent abruptly backward at 

 tip) ; outer toe shorter than middle. 



Nomonyx. (Page 114.) 

 e'. Lores wholly or partially naked ; wing more than 12.00. 



Cairina.^ (Page 100.) 

 d}. Lower portion of tarsus in front without transverse scutellse. 



Dendrocygna. (Page 118.) 



Tarsus longer than middle toe, without claw. (Subfamily AnserincB.) 



c*. Serrations on cutting-edge of upper mandible visible from outside for 



greater portion of the tomium, the latter decidedly sinuated, or 



concave. 



d}. Bill very stout, its depth through base equal to much more than 



half the length of the culmen ; color of adults white, with 



blackish primaries, or else with head and part of neck white, 



the wing-coverts plain bluish gray Chen. (Page 114.) 



cP. Bill weaker and more depressed, its depth through base less than 

 half the length of the culmen ; color of adults never white, or 

 with white head, or bluish gray wing-coverts. 



Anser. (Page 115.) 



c'. Serrations on edge of upper mandible visible onl}^ near angle of mouth, 



the tomium very slightly or not at all sinuated. 



<rZ^ Nostril near middle of nasal fossse ; cutting-edge of upper mandible 



not appi'eciably or regularly sinuated ; bill and feet always 



entirely black ; head partially or entirely black ; tail-coverts 



and crissum white Branta. (Page 116.) 



(P. Nostril at lower anterior extremity of nasal fossse ; cutting-edge 

 of upper mandible appreciably and regularly sinuated, or con- 

 cave ; bill and feet light-colored ; head white (sometimes stained 



1 Cairina Flesiing, Phil, of Zool. 1822, 260. Type, Anas moschata Linn. 



