660 XEMA SABINET, FORK-TAILED GULL. 



gical literature under trying circumstances, which caused pointed personalities. I 

 think, however, that its proper name is not doubtful, as may be made evident. The 

 bird was first mentioned by Macgillivray in the Memoirs of the Werneriau Society for 

 January, 1824, under the name of Larus roseus. This author does not, it is true, give a 

 formal description of the species ; and also acknowledges in his subsequent works, that 

 his name was only a " provisional" appellation. In the following year Richardson, iu 

 the Appendix to Parry's Second Voyage, named the bird Larus rossii, and accompanies 

 his name with a description ; and although this latter author admits that the bird was 

 called roseits before he named it rossii, yet he claims precedence for his name, on the 

 grounds that his was the tirst published description. The priority of Macgillivray's 

 roscus being clearly established, and his name indisputably referring to the species 

 under consideration, the only question is whether it is to be set aside because it was 

 only a "provisional" designation given by one not "commissioned" to describe the 

 object. I think that no valid reason can be given for changing the name. Rules of 

 nomenclature require the adoption in every instance of the first published name when 

 it is by any means identifiable. The first identifiable name to go on record, no matter 

 how it gets there, must be used if it be not antedated in the same genus, and not 

 wholly inept ; and an author has no more right to change a naitie of his own than any 

 one else's. Furthermore, no one can introduce a " provisional " name without becoming 

 bound by it. I am ignorant of what the " personal " or " official " circumstances of this 

 case were ; but according to the record, Macgillivray's only fault was in not standing 

 by the name he originally bestowed. 



Genus XEMA, Leach. 



= Larus, Sab., Linn. Trans, xii, 1818, 520 (L. salnnei). 



= Larus, Prev. & Des Murs, Voy. Venus, 185,5, 277 {L. furcatus). 



^ Xema. Leach, Ross's Voy. Apjj. 1825, p. Ivii (i. sabinei). 



= Xema, Bruch, J. f. O. 1853, 103. ' 



<^ Garni, Macgil., Man. ii, 1842, 241 (X. sab'mei). 



> Crmyrus, Bp., "1854" (L. furcatus). 



Gen. char. Tail forked (here ouly in Larina). Head hooded, with a more or less 

 evident darker collar. Bill black, with light tip. Size moderate and small. 



With a general bearing toward Cliracoccphalus, in the hooded head and other features, 

 the genus is distinguished from this or any group of Larince by the sternine character 

 of forked tail. The name is generally restricted to the type, a " genus" Creagrus being 

 employed for the second known species ; but the latter is apparently a true Xema. The 

 two are readlily distinguished, as follows : 



Small : Wing, 11 inches or less ; tail, lightly forked ; a definite black col- 

 lar bounding the hood ; feet, black sabinei. 



Large : Wing, 16 inches or more ; tail, deeply forked ; black collar incon- 

 conspicuous ; feet, red fukcatum. 



XEMA SABINEI, (S:ib.) Leacli. 



Fork-tailed Gull. 



Larus sahinei, J. Sab., Linn. Trans, xii, 1818, .522, pi. 29.— Jen., Man. 1828, 270.— WiLS., 

 111. Zool. 1831, pi. 8.— Sw. & Rich., F. B. A. ii, 1831, 428.— Nutt., Man. Oru. ii, 

 1834, 295.— AUD., Orn. Biog. iii, 1835, 561, pi. 285 ; Syn. 1839, 323 ; B. Am. vii, 

 1844, 127, pi. 441.— Keys. & Blas., Wirb. Eur. 1840, 95.— Temm., Man. iv, 1840, 

 488.— Naum., V. D. xiii, 1844, pi. 388, f. 1, 2.— Schl., Rev. Crit. 1844, 128 ; Mus. 

 P.-B. iv, 1863, Lari, p. 44.— Degi.., Orn. Eur. ii, 1849, 332.— Midd., Sib. Reise, 

 ii, 1853, 244, pi. 24, f. 5, pi. 25, f. 1 (jmllns et ovum).— Hart., Br. B. 1872, 171 

 (Great JBritaiu, numerous instances). 



Xema saiinei, Leacii, App. Ross's Voy. 1825, p. Ivii, fig. — ; Gen. Zool. xiii, 1826, 177, 

 pi. 20.— Eyt., Cat. Br. B. 1836, 54.— Bi'., List, 1838, 62 ; Comptes Reudus, 1856, 

 771.— Gray, Gen. of B. iii, 1849, 655 ; List Br. B. 1863, 236.— Bruch, J. f. O. 

 1855, 292.— Blas., ibid. 1865, 370.— Lawr., B. N. A. 1858, 857.— Newt., P. Z. S. 

 1861, 401 ; 1871. 57, pi. 4, f. 5 (egg).— Coues, Pr. Phila. Acad. 1862, 311.— Lawr., 

 Ann. Lye. N. Y. viii, 1866, 299 (New York).— Coues, Pr. Ess. Inst, v, 1868, 307.— 

 Dall »fe Baxn., Tr. Chic. Acad. 1869, 306 (Alaska).— Allen, Bull. M. C. Z. iii, 

 1872, 183 (Great Salt Lake).— CouKS, Key, 1872, 317 ; Check-list, No. 558. 



Gavia sabini, Macgil., Man. Orn. ii, 1842, 241. 



" Larus collaris, Sab." {FideBv.) (Where?) 



"Xema coUaris, TuHAcn." {Fide Gray.) (Where?) 



