760 



U. S. p. E. R. EXP. AND SURVEYS — ZOOLOGY — GENERAL REPORT, 



Dendrocygneae.— Bill longer than tlie head; nearly parallel as far as the tip. Nostrils 

 decidedly posterior to the middle of the commissure. Lower part of tibia bare for a con- 

 siderable extent. 



Dendrocygna.— Lamellae of bill hidden by the edge. Hind toe lengthened, more than 

 one-third the tarsus. Wings much rounded ; first primary scarcely longer than 

 the fourth. i. 



ANS R, Linuaeus. 



Atiser, Brisson, Orn. 1760. Type A?ias anser, L. 

 Chen, BoiE, Isis, 1822. Type Anas hyperborea, Gm. 



The characters of Anser have already been given in a preceding page with sufficient detail 

 not to require additions here. As defined, however, it embraces two sections, differing in the 

 following points : 



Chen. — Bill high at base, the upper angle advancing far on the forehead. Width of base 

 of upper mandible more than half the commissure. Lower edge of upper mandible much 

 arched ; the teeth very prominent and large. Lower jaw very deep. Species A. hyperborem, 

 caerulescens ? 



Anser. — Bill not so much elevated at the base as in Chen; the commissure less curved ; the 

 teeth less prominent. Lower jaw not so deep. Species, A. gambelii and frontalis. 



These characters apply pretty well to the American species, but European geese exhibit a 

 very gradual transition between the two. 



Comparative measurements of species. 



' About. 



ANSER HYPERBOREUS, Pallas. 



Suow Goose. 



4n«er caentlmens, Link. Syst. Nat. I, 1766, 198.— Cassin, Pr. A. N. S. VHI, 1856, 12. 



Amer hyperboreus, Pallas, Spic. Zool. VI, 1767, 80, 25.— Bon. Syn. 1828, 376.— Sw. F. B. A. H, 1831, 467.— Nhtt. 

 Man. II, 344.— Add. Orn, Biog. IV, 183i, 562; pi. 381.— Ib. Syn. 273.— Ib. Birds Amer. VI, 

 1843, 212; pi. 381.— Eyto.n, Mon. Anat. 1839, 'J2.— Casslv, Pr. A. N. S. VIII, 1856, U. 

 Anas hyperborea, Gm. I, 504.— Wils. Am. Orn. VIII, 1814, 76; pi. Ixviii and Isii. 

 Anas nivalis, Forbtek, Phil. Trans. LXII, 1772, 413. 

 Tadorna nivea, Brehm, Vug. Deutecbl. 1831, 854. 

 MnsCT- aOiatus, Cassih, Pr. A. N. S. VHI, 1856, 41. 

 Sp. Cn.—AduU. Bill and lege red. Color pure white. Primary quills black towards the end, silvery bluish gray towards 

 he base, where the shafts are white. The spurious quills are also bluish. Inside of wings, except primary quills, white. Im- 

 mature birds have the head washed with rusty. 



