NATURAL SCIENCES OF PHILADELPHIA. 217 



than in any of the following. Bill much as in foregoing, but generally not 

 longer than head, sides converging, l)ase very high, nail at end large, generally 

 forming the whole tip. Lamella as before. Lores definitely feathered (al- 

 Avays?). Wings mediocre, sometimes appendaged. Tail short, rounded, rather 

 many (IC-f )-feathered. Tarsus reticulate ; longer than middle toe (always? ?). 

 Feet moderate, webs sometimes defective. Trachea simple, at least not en- 

 tering sternum. Sexes usually similar. Of large and medium size; strong 

 flyers, good swimmers, and especiallj- good walkers ; do not dive. Genera : 

 Anser, Bernicla, Chloephaga, Chcniscus, Chenalopex, Vlectropterus, Clioristopus, Ce- 

 reopsis, Sarkidiornis, Anseranas, Dendrocygna; but some of these may be only 

 subgenera, on synonyms. 



A rather large group ; none are entirely swan like, but on the other hand 

 some forms grade toward the ducks, and their position is open to discussion. 

 Such especially is Dendrocijgna, but its reticulati;,', not scutellate, tarsi, appa- 

 rently define its position. Plectropterus is the only armed-wiuged swimmer. 

 Chla'phaga and Anseranas have more or less defective webs. The body is not 

 so depressed in the geese as in other subfamilies ; the feet are perhaps further 

 forward; the species stand higli, and walk better than any other AnaHdic. 

 Some are more or less arboricole, like many ducks. 



Subfam. Analinx. — Averaging smaller than either of the preceding ; neck 

 usually much shorter. Bill broad and depressed towards tip ; rarely or never 

 so high at base as in Anserinx; of various details of shape, but rarely if ever 

 gibbous. Lamellaa vertical, in single row. Wings mediocre ; the scapulars 

 or tertials never curly. Tail short, usually rounded, sometimes longer, and 

 pointed ; of varying number of, but generally few, feathers ; its coverts always 

 ample. Feet moderate, rather further forward than in the succeeding ; hallux 

 simple. Body depressed. Head sometimes crested. Sexes dissimilar. Strong 

 flyers, good swimmers, poor walkers, scarcely diving at all ; many are arbori- 

 cole. Genera: Tadorna, Casarca, Lepiotarsis, Anas ci (ijf., Spatula, Aix, Cairina, 

 and others. 



The river ducks have been so extensively subdivided, that many of the dis- 

 tinctions commonly claimed as generic are not of more than specific value. 

 Some of these genera, so-called, could not stand a moment did they not take 

 color from the birds' colors. I think the number must be reduced, and that 

 Anas can conveniently hold some half-dozen of them. 



Suhfam. Fuligulince. — With the characters in general of Anatinfe, hut the feet 

 placed further back and wider apart, apparently, and much larger, with 

 broader webs ; the tarsi short. Hallux with a large hanging lobe. Tail 

 sometimes narrowly long-pointed, its coverts always normal. Scapulars 

 or tertials often curly. Bill frequently gibbous. Strong flyers, very poor 

 walkers, excellent swimmers, and the majority dive well; decidedly marine. 

 Genera: FuUgula et aff., Oidemia el aff., Somateria, and others. 



The sea ducks form a group usually distinguishable on sight from the pre- 

 ceding, and well characterized; yet it is difficult to find any positive feature 

 applicable to all, except the large-lobed hallux ; this is simple in the river 

 ducks. But the feet are comparatively much larger. The species are mostly 

 marine, diving well, and scarcely walking. As in the preceding group, the 

 genera are altogether too many; but, likewise as in that case, I am not pre- 

 pared to speak authoritatively as to the amount of reduction that would be 

 desirable. Above, I only indicate principal series or sets of genera. Thus 

 FuUgula has grouped about it Fulix, Aythya, Nyroca, Clangula, &c., just as Anas 

 has Netlion, Querquedula, Mareca, IJaJila, Chaulelasmus, &c. Oidemia might 

 contain all the "Scoters," as Felionetla, Melanetla, &c. Another central point 

 has grouped about it forms like Ilistrionicus, Folysticta, Camptolipmus, Harelda, 

 &c. Somaleria will embrace all the '' Eiders " with gibbous, partly feathered 

 bill. This is merely an indication of the grade of differences that I would 

 be inclined to consider generic. 



1869.] 



