888 
U. S. P. R. R. EXP. AND SURVEYS — ZOOLOGY GENERAL REPORT. 
COLYMBUS TORQUATUS, Brunnich. 
The Great Northern Diver; The Loon. 
Colymbus torquatus, Brunn. Orn. Bor. 1764, 134. 
Colymbus glacialis, Linn. Syst. Nat I, 1766, 221.— Forster, Phil. Trans. LXI1, 1772, 383.— Wils. Am. Orn. IX, 
1824, 84, pi. lxxiv. — 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. cccclxxvi. 
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 . 
Mult. — 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. 
Hab. — 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 head of a young individual from the 
Pacific coast; two ot the young from New Mexico. Individuals vary considerably in size, some 
measuring 36 inches in length. 
Catal. 
No. 
Sex. 
Locality. 
When col- 
lected. 
Whence obtained. 
Orig'l 
No. 
Collected by— 
Length. 
Stretch 
of wing;? 
Wing. 
Remarks. 
1550 
2161 
3 
Q 
May 18, 1844 
Apr 26,1845 
31.50 
31.00 
54.00 
56.00 
14.00 
14.50 
Cab. of Geo. N. 
Lawrence. 
962 
9910 
•1516 
4580 
9920 
13 00 
Dr. Cooper .... 
30.00 
31.00 
Color of iris blood red, 
Stpiln.-nnm W T ___ 


14.50 
14.00 
575 

COLYMBUS ARCTICUS, Linnaeus. 
The Black-throated Diver. 
Colymbus arcticus, Linn. Syst. Nat. I, 1766, 221.— Bonap. Syn. 1828, No. 369.— Rich, and Sw. F. B. A. II, 1831, 
475.— Nutt. Mao. II, 1834, 517.— Aud. Orn. Biog. IV, 1838, 345.— Ib. Birds Am. VII, 1844, 
295; pi. eecclxxvii. — Gray Genera, III, 620; pi. clxxi. 
