434 LAMELLIROSTEAL SWIMMERS — ANSERES. 



The Geese of the Northern Hemisphere vary so much in the details of form, that the genera 

 usually recognized are far more artificial than natural, their definition being of the utmost dilficulty, 

 scarcely two species being exactly alike in the minutiaj of external anatomy. No great violence 

 would be done their true relationship, were all the North American Geese, except Philacte and Den- 

 drocycna, referred to a single genus, Anser; but for convenience of classification it may serve the 

 purpose best to admit a limited number of genera, defined as follows : — 



ANSEREjE. 



At Bill variable, the nasal cavity ^ situated near the middle of the maxilla, elongated, and indis- 

 tinctly defined; " nails" of tlie bill rather small, occupying much less than the terminal 

 third of the bill. 



a. Colors variable, l»ut head and neck with little, if any, black. Bill and feet light colored 



(usually reddish) in adult. 



1. Chen. Bill very robust, the culmen slightly, the lower outline of the mandible decidedly, 



convex ; very slightly depressed immediately behind the thickened nails ; commissure 

 widely gaping (except in G. Rossi). Head and neck of adult white ; some species entirely 

 white in adult dress, except primaries. Bill and feet reddish in the adult. 



2. Anser. Bill more slender, the culmen gently concave, the lower outline of the mandible 



slightly concave anteriorly ; decidedly depressed immediately behind the rather thin nails ; 

 commissure nearly or quite closed, by the close approximation of the tomia. Head and 

 neck never white, and no species entirely white (normally). Bill and feet light colored 

 in the adult. 



b. Colors dark, with the head and neck chiefly black ; Isill and feet deep black at all ages. 



3. Bernicla. Bill usually much as in Anser ; all the characters, except those defined above, 



exceedingly variable. 

 B. Bill depressed and broad, the nasal cavity situated in the basal half of the maxilla (its pos- 

 terior end nearly or quite touching the frontal feathers), broadly ovate, and distinctly 

 defined ; nails of the bill very large, occupying nearly the terminal third of the bill. 



4. Philacte. Color bluish, variegated with whitish borders to the feathers and subterminal 



dusky crescentic bars ; exposed portion of the tail white. Adult with the head and nape 

 white, the bill and feet light colored ; young with the head plumbeous, the bill and feet 

 dusky. 



DENDROCYCNEiE. 



5. Dendrocycna. Bill longer than the head, the edges nearly parallel, the lamellfe entirely 



concealed by the overhanging edge of the maxilla. Lower part of the tibia bare for a 

 considerable distance. Tarsus shorter than the middle toe with claw, but longer than the 

 middle toe without claw. 



Besides the species properly considered to be American, another has been recorded as occurring 

 within our limits, on the strength of a single specimen shot on Long Island, N. Y. This is the 

 Egyptian Goose, Chenalopex ccgyjotiacus, of South Europe and Northern Africa — a common species 

 in aviaries ; so that it is altogether probable that the example in question was one escaped from 

 confinement. The genus Chenalopex differs from all the North American Geese in its style of 

 coloration, the wing-coverts being white, and the secondaries metallic purplish ; the maxillary 

 tomium hangs over the mandible so as almost to conceal it terminally, the bill being much de- 

 pressed at the end, and very deep through tlie base ; the legs are lengthened, the tarsus consider- 

 ably exceeding the middle toe in length ; the hallux well developed. The colors of G. a'gyjitiacus 

 are as follows : Head whitish, with an elongated patch surrounding the eye, and a collar encircling 

 the lower part of the neck, chestnut rufous ; neck light brownish gray ; breast, back, scapulars, 

 sides, and flanks pale fulvous, finely undulated with dusky ; outer webs of tertials (inner second- 

 aries) ])lain chestnut-rufous ; abdomen, anal region, and wing-coverts white, the greater coverts 

 barred near the end with black, forming a single narrow bar across the wing ; secondaries dark 

 metallic purplish ; primaries, primary-coverts, and alulye, rump, upper tail-coverts, and tail plain 



1 By "nasal cavity" is here meant not the opening of the external nostrils, but the opening in the 

 maxillary bone, cliiefiy covered by tlie overlying membrane. 



