LAEUS TRIDACTYLUS, KITTIWAKE GULL 645 



Lams tridaciylm, Linn., Fn. Suec. 55; Syst. Nat. i, 1766, 224.— Gm., Syst. Nat. i, 1788, 

 .'J95.— Lath., Iiid. Orn. ii, 790, 8i8.— Eetz., Vu. Siiec. 1800, 154.— Nilss., Fn. 

 Siieo. ii, 174.— .SoiiiEifi''., Mus. Orn. 17T9, 64.— Mev. & Wolf, Tascli. Duuts. ii, 

 1810, -180.- Temm., Man. 18ir>, 502 ; ii, 1820, 774.— ViKu.r.., Nonv. Diet, xxi, 1818, 

 503 ; Fn. Franf. 39.— Fabeh, Prod. Isl. Ovn. 1820, — .— Breiim, Eur. Vcig. 18-2:3. 

 705.— Br., Svn, 1828. 359.— S\v. et Eicn., F. B. A. ii, 1831, 423.— Norr., Man. ii, 

 183J, 298.— Jen., Man. 1835, 274.— AuD., Orn. Biog. iii, 1835, 186, pi. 224 ; Syn. 

 1839. 326 ; B. A. vii, 1844, 146, pi. 444.— Sciiixz, Eur. Fn. 1840, ;!85.— Xaum., V. 

 D. X, 1840, 322, pi. 202.— Keys. & Blas., Wirb. Eur. 1840, 9,5.— ScriL., Kev. Grit. 

 1844, 126.— DeKay, N. V. Fauna, ii, 1844, 313.— GiR., B. L. I. 1844, 361.— Schl., 

 Mus. P.-B. iv, 1803, Lan, p. 30.— COUES, Key, 1872, 314. 



Caria tridavhjJu, BoiE, Isi'.i, 1822, 563. 



Cheimoneu iridaotyla, Kaup, Sk. Eut. Eur. Thierw. 1829, 84. 



Laroides iridaotyla, Bkehm, V. D. 1831, 754. 



Bissa tridactijltt, Bl'., List, 1838, 62 ; Consp. Av. ii, 1856, 225 ; Conipt. Eeud. 1856, 770.— 

 Macuil., Man. ii, 1842, 250.— Gray, Gen. of B. iii, 1849, 655.— Bruch, J. f. O. 

 1853, — ; 1855, 284.— Lawr., B. N. A. 1858, 854.— CorivS, Pr. Phila. Acad. 1861, 

 247; ibid 1862, ,304.- -Wheat., Ohio A^uic. Rep. l8fiU, No. 270 (Lake Miehi- 

 gan).— ElDGW., Ann. Lye. N. V. x, 1874. 393 (the .same).— BoARDJi., Pr. Bo.st. 

 Soc. ix, 1862, 131.— Verk., Pr. Es8. Inst, iii, 1862, 101.— Allen, ibid, iv, 1864, 

 90.— CouES, ibid. V, 1868, 30S.— Lawr., Ann. Lye. N. Y. viii, 1806, 2ii9.— Malmg., 

 J. f. O. 1865, 202.— Kewt., Ibis, 1805, 508.— Dale & Bann., Tr. Chic. Ac.ad. 1869, 

 305 (fJTotefZiOT).— TiiRM'.., B. E. Pa. 1869, 38.— Finsch, Abb. Vat. iii, 1872 

 (tioke&MJ)-— Blas., J. f. 0. 18G5, 384. 



Larus ncnius, Sciijefh., Mus. Orn. 1779, 64. 



Larus torquaius, " caiiiis" et garia, Pali.., Zoog. R. A. ii, 1811, 328, 329, 330. 



Bissa briinnichii. Leach, Stepb. Gen. Zool. xiii, 181, pi. 21. 



Rma cinerca. Eyt., Cat. Br. B. 1836, 52. 



Laroides minor, Brehm, V. D. 1831, 756. 



DiAG. L. pidihus sub-iridaciylis, fuscis, rostro Jiaco-riiescente. 



Hab. — Arctic regions of both hemispheres. South in winter on the Atlantic coast to 

 the Middle .States. 



Bill rather longer than the tarsus, about equal to the middle toe without the claw, 

 stout at the base, ta.pering toward the tip, which is attenuated, acute, and decurved. 

 Convexity of culiueu regular from the base to the apex. Eminentia symphysis mod- 

 erately developed, but acute. Gonys concave, as are also the rami. Nostrils rather far 

 forward, lateral, linear, direct. Feathers encroach far on the upper mandible, within a 

 tenth of an inch of the nostrils, and meet over the culmea some distance in front of 

 the base. Their extent on the sides of the lower mandible is uuich less, but between 

 the rami they reach to the apex of the mental space, which is narrow and acute autc.> 

 riorly. The formation of the palate as in Larus generally, but the ridges all broad and 

 distinct, more thickly covered with larger papillse than in most species. Tongue large, 

 fleshy, corneous only for its anterior half. Wings very long and acute ; first primary 

 largest, second nearly equal to it, rest rapidly graduated. Tail rather long for this 

 subfamily, perfectly square. Feet short and stout, the tarsus little comi)ressed ; the 

 reticulations on its posterior aspect, as well as on the inferior surface of the toes, 

 rougbeued and elevated into small conical papillse. The scutellatiou of the tarsus an- 

 teriorly breaks up into small polygonal reticulations some distance below the tibio- 

 tarsal joint. Anterior toes all long; the interdigital webs broad, full, with unincised 

 margins. Hallux typical of the genus. Claws short, stout, little arched, not very 

 acute, absent on the hallux. 



Adull, brcediny plumage.— Color of bill light yellow, clouded with olivaceous. Head 

 and ueck all round, under parts aud tail, pure white. Mantle rather dark bluish or 

 cinereous-blue, the tertiaries aud secondaries of the same color nearly to their tips, 

 which are white. Primaries; the first very light bluish-white, w.thout white apex, its 

 outer web, and its inner web for about two inches from thb tip, black ; second like the 

 first, bnt without the black outer web, its tip beirg black for nearly the same dihtanoe 

 as the first, its apex with a minute white spot ; on the thir.l and fourth the black tips 

 grow shorter, while the af ices are more broadly white ; this lessening of the black on 

 each feather is exactly proportional to the shortening of the successive quills, causing 

 the bases of all the black tips to be in the same straight line. A sub-apical black spot 

 is usually present on one or both webs, but is sometimes absent. Legs and feet dusky 

 olive. 



Adult in u-hitn: — Occiput, nape behind, and sides of the breast, clouded over with 

 the color of the back, deepening into slate over the anriculars. A very small but well- 

 defined ante-ocular lunula. Otherwise as in summer. 



Young. — Bill black; an ante-ocular lunula, and a post-ociilar spot, dusky slate. A 

 broad transverse bar across the neck behind, the whole of the lesser and median wing- 

 coverts, the bastard quills, the tertiaries, except at their edges, aud a terminal bar on 



