ANATIDM — MERGIN.E: MERGANSERS. 947 



N03I0'NYX. (Gr. vojxo^. nomas, law, order; ow^. onux, nail: nail of bill ordinary.) RuD- 

 DKK DUOKS. Character of Erismatura, but nail of bill not peculiar, and outer toe shorter 

 than middle one. Inner secondaries so lengthened as to fold over primaries in closed wing. 

 One species. 



N. domi'nica. (Of St. Domingo.) St. Domingo Duck. Adult $: General color ferru- 

 ginous, or chestnut-red, more or less extensive and continuous on under parts and around neck, 

 lightening on belly to rusty-yellowish, varied with black centres of the feathers on the back, 

 scapulars, and flanks; most of head black ; large white area on wing formed by ends of many 

 of the coverts and bases of corresponding secondaries; axillars al.M) white ; tail black. Bill 

 blue, black-tipped; feet dark: eyes brown, with a bluish ring. Adult 9 or young $: Back 

 blackish, spotted with yellowish-brown ; general rusty color dappled with dusky; two blackish 

 stripes on each side of head, one through eye, the other lower down, each bordered above with 

 buff; speculum white, as before; bill (d)scurcd. Length 13.00-14.50; wing 5.50; tail 4.00; 

 tarsus 1.00; culmeu 1.40. A small, curious Duck of Central and South America and the West 

 Indies, N. to the Lower Kio Grande, accidental in the U. S. Liike Chamjilain, N. Y. and Lake 

 Koshkonong, Wisconsin (see Proc. Bost. Soc Nat. Hist, vi, .'575; xiv, 154; Amer. Nat. v, 

 441 ; Baird, B. N. A. 1858, 925) and in Massachusetts near Maiden (Auk, 1889, p. 336). 



Subfamily MERGING : Mergansers. 



Bill narrow, more or less nearly cylindrical, nail hooked and overhanging, lamellae highly 

 developed into prominent serrations, nasal fossae lengthened and narrowed. Nostrils median 

 or siib-basal. Tarsi compressed, anteriorly scutellate, with smaller plates on sides and behind, 

 ^-f as long as middle toe and claw. Hind toe lobate. Tail rounded, usually ^ or more the 

 length of the pointed wings, l()-18-feathered. Head usually crested. Excepting character of 

 bill, Saw-bills or Fishing Ducks are simply Fuligulince, somewhat modified in adaptation to a 

 more exclusively animal regimen ; the lamellaB of the bill become detainers of large objects, not 

 sifters or strainers of minute things. Tlie princi{)al p<iint in their economy is ability to pursue 

 fish under water, like Cormorants, Loons, and other birds of lower orders. The nature of their 

 food renders their flesh rank and unpalatable; in buying a "Duck,'' notice the bill that it be 

 not cylindric, hooked, and saw-toothed. The flap of the hind toe is as in any Sea Duck; the 

 tarsi are much compressed. The gizzard is rather less muscular than in most Ducks ; intes- 

 tines and their cceca shorter ; syringeal capsule of $ very large, irregular, partly membranous ; 

 the trachea has other dilatations (fig. 3). Birds of this group inhabit fresh as well as salt 

 water, and are abundant in individuals if not in species. There are about 8 species, chiefly of 

 the Nortlicrn Hemisphere, but .several occur in South America : wo have 3, commonly and 

 properly referred to 2 genera, Merganser and Lophodytes ; besides a fourth, which is only a 

 rare straggler. 



Annli/sis of Genera and Species. 



Tarsus shorter than culmeii. Tail of IS feathers. 



Bill not shorter th;ui head, mostly red. Serrations of bill acute, recurved, claw-like. Tarsus about two-thirds 

 as long as middle toe. Tail about half as long as wings. Crest low, ttiwsy, oitiiutal, if any. Head green or 

 brown. (Mkroanser.) 

 Nostrils near nuddle of hill. Frontal feathers beyond those on side of bill. Crest scarcely developed <f 



with breast uncolored '"• nmrrirtiuiit 



Nostrils near base of bill. Frontal feathers not beyond those on siile of bill. Crest better develoi»ed. cT 



with breast and sides colored "•• setTiitnr 



Bill shorter than head, mostly black. Serrations of bill low, obli(iue, not hooked. Tarsus about half oa long ait 

 middle toe. Tail more than half as long as wing. Crest of cf highly developed, erect, compressed, semicircu- 

 lar, coronal as well as occipital. (Lophodytes.) 



Nostrils near base of bill. Frontal feathers produced beyond those on «id.w -f I'll /. ciiculUtlut 



Tarsus longer than culmeu. Tail of Ki feathers. (Mrkous.) 



A .straggler fnim Kiin.pe "•• "IMItU 



