1. COLYMBUS, 495 



Orn. ii. i3. 802 (1790) ; Temm. Man. d'Orii. p. 604 (1815) ; Vieill. 

 N. Diet. iVIIist. Nat. xxvii. p. IH) (1818). 



* Colymbus arcti(-us, Gmel S. N. i. pt. ii. p. 587 (1788) [part ; 

 America]; Lath. Lid. Orn. ii. p. 800 (1790) [part]; Swains. cV 

 Richards. Faun. linr.-Amer. p. 475 (18-31) ; And. Orn. Bior/r. iv. 

 p. 345, pi. 34G (18.-38); id. Ii. Amer. vii. p. 295, pi. 477 (1844): 

 Baird, B. N. Anicr. p. 888 (i860) ; Walker, Ibis, 1860, p. 167 

 [Bellot Straits, Arctic America] ; Blakiston, Ibis, 1863, p. 154 

 [Brit. N. America] ; Cows, P. Essex Inst. v. p. 309 (18i58) [New 

 England] ; Dall ^- Bann. Tr. Ckicaffo Ac. i. p. 307 (1869) ; 

 Havtinrj, P. Z. S, 1871, p. 119 [Bering Straits]; Coues, Key N. 

 Am. B. p. 334 (1872) [part ; N. America]; Finsch, Abh. Nat. Ver. 

 Bremen, iii. p. 74 (1872) ; Ridgw. Ann. Lye. N. York, x. p. 392 

 (1874) [Illinois] ; Stearns ^ Coues, N. Enql. B.-life, p. 389 

 (1833) ; Coues, Key N. Amer. B. 2nd ed. p. 791 (1884) [part]. 



Mergus striatus, Bonnat. Tahl. Encycl. Meth. i. p. 73(1790). 



Black-throated Diver, Nutt. Man. Orn. p. 517 (1834) [parti. 



Colymbus pacificus, Lawr. in Baird's B. N. Amer. p. 889 (1860) 

 [Piiget Sound, California]; C^ioper ^ Suckl. N. II. Wash. Terr. 

 p. 279 (1860) ; Coues, P. Ac. PhUad. 1862, p. 228, 1866, p. 100: 

 id. Ibis, 18156, p. 272 [habits]; Brotvn, Ibis, 1868, p. 427 

 [Vancouver I.] ; Rid(ju\ Bull. U. S. Nat. Mas. xxi. p. 56 (18S1) : 

 Merriam, Auk, ii. p. 63 (1885j [Point Barrow, Alaska; migra- 

 tion]. 



Colymbus arcticus, var. pacificus, Ross, Nat. Hist. Rev. 1862, p. 289 

 [Mackenzie R.] ; Coues, Key N. Amer. B. p. 335 (1872) ; id. 

 B. N.-West,^^.ni (1874). 



Colymbus arcticus paciKcus, Cuues, Key N. Amer. B. 2nd ed. p. 791 

 (1884). 



Urinator arcticus, A. O. TJ. Checkl. p. 76 (1886) ; Ridgw. Man. N. 

 Am. B. p. 7 (1887) [part]; Nelson, Rep. N. H. Alaska, p. 3C. 

 (1887) ; Clarke, Auk, vii. p. 320 (1890) ; MacFarl. P. U.S. Nat. 

 - TlfMS. xiv. p. 416 (1891) [Arctic America] ; Hatch, B. Minnesota, 

 p. 12 (1892); Butcher, Auk, x. p. 265 (1893) [Long. I.]: 

 Mcllwraith, B. Ontario, ed. 2, p. 32 (1894). 



Urinator pacificus, Stejn. P. U.S.Nat. Mus. v. p. 43 (1882) ; Baird, 

 Brew. ^- Ridqw. Water-B. N. Amer. ii. p. 455 (1884) ; Turner, 

 Auk, ii. p. 159 (1885) [Nearer Is., Alaska]; A. O. U. Checkl. 

 p. 76 (188(i); Ecerniann, Auk, iii. p. 88 (1886) [Ventura Co., 

 Cal.]; Nelson, Rep. N. H Alaska, p. 37 (1887) ; Ridyiv. Man. N. 

 Amer. B. p. 8 (1887) ; MacFarl. P. U.S. Nat. Mus. xiv. p. 416 

 (1891) [Arctic Ameiica] ; Stejn. P. U.S. Nat. 3/to-. xv. p. 291 (1892) 

 [Hakodadi] ; Lawr. Auk, ix. p. 353 (1892) [Washington, D.C.] 



Gavia arctica, Allen, Auk, xiv. p. 312 (1897). 



Gavia pacifica, Allen, Auk, xiv. p. 312 (1897) ; Grinuell, Auk, xv 

 p. 124 (1898) [Sitka]. 



Adult in hreeding-plumage. Differs only from tjpical C. arcticu.'i 

 in the paler colour of the nape and back of the neck, which is dull 

 smoky-white. Tail composed of 16 or 18 feathers. Total length 

 about 24 inches, culmen from feathers on forehead 2-2-4, wing 

 11"4-11*7, tail 2-2-3, tarsus 2-7-3, outer toe and claw 3-6-4. 



Adult in non-hreeding plumage and young similar to G. arcticits. 



* I have not seen any specimen of typical C. arcticus from A'ortJa America ; 

 all appear to belong to tiie pale-naped furm C. pacificus. 



