908 



S YS TEMA TIC S YNOPSIS. — LAMELLIROSTRES — AN SERES. 



Subfamily ANATIN/E: River Ducks. 



Tarsi scutellate in front ; hind toe simple (in Fuligulina-, liind toe with a flap or lobe). 

 This expression separates the present group from all North American examples of foregoing 

 and succeeding subfamihes, although it is not a perfect diagnosis. The neck and legs are 

 shorter than they average in Geese, while the feet are smaller than in Sea-ducks, the toes and 

 their wehs not being so highly developed. No Anatincs are so exclusively maritime as most 



Fuligulince ; yet they 

 are by no means con- 

 fined to fresh waters, 

 and some species con- 

 stantly associate with 

 Sea-ducks. They feed 

 extensively, like most 

 Geese, upon succulent 

 aquatic herbage, but 

 also upon various animal 

 substances ; their flesh is 

 almost without excep- 

 ti(in excellent. They do 

 lint dive for food. The 

 sexes are almost inva- 

 1 ial)ly markedly distinct 

 in color; the young re- 

 semble the 9 ; the wing 

 liiis usually a brilliant 

 s|ieculum, which, like 

 nther wing-markings, is 

 alike in both sexes. In 

 various of the River- and 

 Sea-Ducks the $ as- 

 ■-mnes in summer atem- 

 irary, dull, protective 

 I image more or less 

 <o that of the 9. The 

 9 incubates, and cares 

 i(ir the young. As com- 

 [);ued with Anserince, a 

 good anatomical chai'ac- 

 ter is the very general 

 presence in Anatince (as 

 also in FnUfpilin^) of the tracheal tympanum or bulla ossea already mentioned (p. 891); it usu- 

 ally marks the drakes only, but may occur in the other sex, and its variations in structure 

 afi'ord a generic distinction in some cases. Although the diflerence between any ordinary Duck 

 and a true Goose is obvious at a glance, there is no sharp line of distinction between the two 

 subfamilies. We have a connecting link in the genus Dendrocygna, as already stated ; and 

 though the Shieldrakes themselves are undoubtedly anatiue rather than anserine, some of their 

 near relatives occupy an ambiguous position. The genus Casarca, which I now first intro- 

 duce to the Key, is a true Shieldrake, and some related exotic forms will be found noted 

 beyond. Of genuine Anatince there are rather more than 60 species, generally distributed over 



Fig. 635., — Black-bellied Tree Duck. 

 D. G. Elliot.) 



(From " Wild Fowl of North America," by 



