888 



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



COLYMBUS TOKQUATDS, Briinnich. 



The Great Northern Diver ; The liOon. 



Colymbus torquatus, Brunn. Orn. Bor. 1764, 134. 



Colymbus glacialis, Linn. Syst. Nat, I, 176G, 221.— Fokster, Phil. Trans. LXII, 1772, 383.— "WiLs. Am. Orn. IX, 

 1894, 84, pi. Ixxiv.— BoNAP. Syn. 1828, No. 368 —Rich. & Sw. F. B. Am. II, 1831, 474 — 

 NuTT. Man. II, 1834, 513.— Aud. Orn. Biog. IV, 1838, 43, pi. 306.— Ib. Birds, Am. VII, 

 1844, 282 ; pi. occclxxvi. 



Colymbus immer, Linn. Syst. Nat. I, 1766, 222. (Young of year.) 



Sp. Ch. — Bill compressed, strong and tapering, outline of upper mandible nearly straight, very slightly curved ; the lower 

 mandible has a groove underneath, running from the junction of the crura towards the point ; the tail consists of twenty 

 feathers . 



Adult. — The head and neck are dark bluish green, the upper part and sides of the head glossed with purple ; there is a small 

 transverse mark on the throat, composed of white feathers of a quill like form, distinct from each other and placed longitudinally 

 on each side of the neck ; lower down are larger patches of white, of the same peculiar form, and running in the same direction ; 

 these almost meet behind, and in front are about one inch apart ; the effect of these pure white feathers, relieved by the dark 

 color of the neck, is very beautiful ; the upper plumage and wing coverts are deep glossy black, beautifully marked with pure 

 white spots placed in regular transverse rows, slightly curving downwards ; these spots, on the upper part of the back, are small 

 and nearly round, but as they descend lower on the back increase in size and become quadrangular in form, being largest on the 

 scapularies ; on the lower part of the back, upper tail coverts and sides (which are black,) the spots are small and round ; the 

 sides of the neck, near the shoulder, are beautifully lineated with black and white ; the primaries, secondaries and tail brownish 

 black ; the under surface glossy white, with a narrow band of dusky feathers crossing the lower part of the abdomen, and 

 marked with small white spots ; lower tail coverts blackish brown, tipped with white ; bill black ; iris deep bright red ; tarsi and 

 feet greyish blue externally, tinged on the inside with pale yellowish red ; webs brownish black ; claws back. 



Length, 31 inches ; wing, 14 ; tarsus, 3^ ; bill, 3 ; height at base, 1. 



Young. — The plumage above is greyish black, the feathers of the back margined with greyish white, the under plumage pure 

 white, bill yellowish with the ridge of the upper mandible dusky. 



Hob. — Very generally distributed ; it is abundant on the Atlantic coast, in the lakes of the interior and the fur countries 

 Specimens are in the collection from the Pacific coast and from New Mexico . 



There are two specimens in adult plumage^ and a liead of a young individual from tlie 

 Pacific coast; two ot the young from New Mexico. Individuals vary considerably in size, some 

 measuring 36 inches in length. 



COLYMBUS AEOTIOUS, Linnaeus. 



The Black-throated Diver. 



Colymbus anliaa, Linn. Syst. Nat. I, 1766, 231.— Bonap. Syn. 1828, No. 369.— Rich, and Sw. F. B. A. II, 1831, 

 475.— NuTT. Man. II, 1834, 517.— Aud. Orn. Blog. IV, 1838, 345.— Ib. Birds Am. VII, 1844, 

 295; pi. ccoclxxvii. — Gray Genera, III, 630; pi. clxxi. 



