624: LARUS MARINUS, BLACK-BACKED GULL. 



placed by a pearly gray-bine shafle like that of the mantle. Young birds in all stages 

 are paler and grayer than the corresponding stages of argeniatxis. Agreeing with leiv- 

 copleru/) in respect of size, glaucescens may be immediately known by the pattern of the 

 primal ii-s ; the pearly-blue color continuing undiminished in intensity to the tips of 

 the feathers, instead of fading gradually into white as in glaucm and leiicopterus. 



I have never seen a specimen purporting to he " chalcopterua," which Mr. Lawrence 

 admitted In 1858. As described, it is " exactly like leueopteru8, except on the primaries, 

 lyhich are ashy-gray, with rounded white apical spots" — which is precisely the char- 

 acter of glaucescens. The young are said to be " dark gray, as in glaucopterus" (of Kitt- 

 litz, = glaucmeens, Licht.) There is not the slightest likelihood that it is anything 

 more than glaucescens, probably in somewhat immature condition. 



LAEUS MAEmUS, Linn. 



Great Black-backed Gull. 



Larus marinus, Lrxx., Syst. Nat. i, 1766, 225.— Gm., Svst. Nat. i, 1788, 598.— Lath., Ind. 

 Orn. ii, 1790, 1513.— Temm., JIan. 1815, 490.— BoiE, Isis, 1822, 562.— Steph., Gen. 

 Zool. xiii, 1826, 186.— Flem., Br. An. 1828, 140.— Bp., Syn. 1828, — ; List, 1838, 

 63.— NuiT., Man. u, 1834, 308.— Brbhm., V. D. 1831, 731.— .Jen., Man, 18.35, 

 278.— Eyt., Cat. 1836, 53.— AuD., Orn. Biog. iii, 1835, 305 ; v, 1839, 636 ; pi. 241 ; 

 Svn. 1839, 329; B. Am. vii, 1844, 172, pi. 450.— Naum., V. D. x, 1840, 439, pis. 

 268, 2G9.— Keys. & Blas., Wirb. Eur. 1840, 97.— Macgil., Man. Om. ii, 1842, 

 244.— GiE., B. L. L 1844, 361.— ScHL., Rev. Crit. 1844, 124 ; Mus. P.-B. ix, 186.3, 

 Lari, p. —.—Gray, Gen. of B. iii, 1849, 654; List Br. B. 1863, 231.— Lawr., B. 

 N. A. 1858, 844 ; Ann. Lye. N. Y. yiii, 1866, 299.— Bry., Pr. Bosr. Soc. viii, 1861, 

 72.— CouES, Pr. Phila. Acad. 1861, 244 ; ibid. 1862, 295; Pr. Ess. Inst, v, 1868, 

 306 ; Key, lis72, 312.— Boaedm., Pr. Boat. Soc. ix, 1862, 131.— Veer., Pr. Ess. 

 Inst, iii, 1862, 160.— Ai,len, iUd. iv, 1864, 90.— Sharpe & Dress., B. Eur. pt. 

 XV, Dec. l.~72. — RiDGW., Ann. Lye. x, .391 (Lake Michigan, Velie); and of authors. 



Leucus marinus, Kaup, Sk. Ent. Ear. Thierw. 1829, 66. 



Bominicamis marinus, Bruch., J. f. 0.1853,100; 1855, 280.— Bp., Consp. Av. ii, 1856, 

 213; Compt. Rend, xlii, 1856, 770. 



Lams niger, Beiss., Orn. vi, 1760, 158. 



Zarus na:rius, Linn., Syst. Nat. i, 1766, 225.— Gm., Syst. Nat. i, 1788, 598.— Lath., Ind. 

 Orn. ii, 1790, 814. 



Zarus albus, Mull., Syst. Nat. Suppl. 1776, 108. 



Zarus maculatus, BoDD., Tabl. P. E. 1783, 16. 



Zarus maj-imus. Leach, Cat. 1816, 40.— Brehm, V. D. 1831, 728. 



Zarus mulleri etfabricii, BEEH.At, V. D. 1831, 729, 730. 



DiAG. Z. staturd maximus, pallia scMstaceo-nigro. Long. 30.00 poll. 



Sal). — ^American and European coasts of the Atlantic. South in winterj^to Long 

 Island (to Florida, Aud.). Great Lakes and the Mississippi (Aud.). 



Adult, breeding plumage. — Size very large ; general form strong, compact, and power- 

 ful. Bill very stout, deep at the angle, rather short for its height ; culmen toward the 

 end exceedingly convex, so much so as to make a tangent to it at the point where the 

 tip of the lower mandible touches it perpendicular to the commissure. Symphyseal 

 eminence very large and prominent ; tarsus but little if any longer than the middle 

 toe and claw, compressed, rather slender for the size of the bird. Interdigital mem- 

 branes broad, scarcely emarginate. Bill bright chrome, the tip of both mandibles 

 diaphanous. A large bright vermilion spot occupies nearly the terminal half of the 

 lower mandible and encroaches a little on the upper. Edges of jaws bright vermilion. 

 Palate and tongue pale orange-red. Eyelids vermilion. Iris pale lemon-yellow. Legs 

 and feet pale flesh-color. Mantle intense slate-color, nearly black, with a purplish re- 

 flection. The secondaries and tertials broadly tipped_ with white, the line of demarca^ 

 tion distinct. Primaries : first, black, scarcely lighter at its base, its tip white for 2J 

 inches, its shaft white inferiorly, and superiorly along the white portion of the feather ; 

 second, like the first, but its base lighter, the white tip less extensive, and interrupted 

 by a narrow bar of black on one or both webs; third, fourth, fifth, broadly tipped with 

 white, their bases of a lighter shade of slate than the second, aud fading into white at 

 the junction with the broad black aubterminal band. 



Adult in u-intir. — As in summer, but the head and neck streaked with dusky. 



Young-of-the-year. — As large as the adult ; the bill as large, but not so scrong, nor the 

 eminence so well developed ; wholly black. Upper parts wholly dusky chocolate- 

 brown, mottled with whitish and 1-ght rufous, the latter on the back aud wings, the 

 feathers being tipped and the wing coverts deeply indented with this color. Under - 

 parts mottled with white or rufous-white and dusky, the throat mostly immaculate. 



