526 



PROCEEDINGS OF THE NATIONAL MUSEUM. 



VOL. 49. 



Mathews has discovered, properly applicable to the Austrahan form 

 of Sterna anaeiheta. 



Detailed measurements of specimens examined are as follows: 



Measurements of specimens of Thalasseus bergii poliocercus. 



Museum and No. 



Sex. 



Locality. 



Date. 



Collector. 



•a a 



U.S.N.M. 716841.. 



M. C. Z.87811 



M.C.Z. 87821 



U.S.N.M. 2118961. 



Male. 



..do.... 

 Male?... 

 Female . 



M. C. Z. 12018 1. . 



M.C.Z. 27589.. 

 M. C. Z. 56054 1. 

 M.C.Z. 560551. 

 M. C. Z. 56056 1. 

 M. C. Z. 56057 1. 



Female? 

 Juvenal. 



Illawarra, New 

 South Wales, Aus- 

 tralia. 



Tasmania 



do 



Bass Strait, Victoria, 

 Australia. 



Melbourne, Victoria, 

 Australia. 



Tasmania 



Australia 



do 



do 



do 



W. Robertson. 

 do 



J. McCoy. 



Jan. 3, 1897 



July 30,1897 



Dec. 29,1896 



Feb. 7, 1897 



M.J. Flood. 



do 



do 



do 



mm, 

 350 



334 

 340 

 285 



332 



320 

 328 

 320 

 337 

 331 



mm. 

 160 



158 

 146 

 158 



173 



mm. 

 63 



59.5 



59 



55 



56 



43.5 

 66 



131 

 131 



142 155 

 179 63 

 165 159.5 



mm. 



28 



31 

 30 

 27.5 



27 



26.5 



27 



26.5 



27 



27 



THALASSEUS BERGII GWENDOLENAE (Mathews). 



Sterna bergii gwendolenae Mathews, Novit. Zool., vol. 18, Januaiy 31, 1912, p. 

 208 (Rockingham, Western Australia). 



Subspecific characters. — Like Thalasseus hergii poliocercus and Tha^ 

 lasseus hergii pelecanoides, but decidedly larger, and with upper parts 

 paler than either. 



Measurements.^ — Wmg, 343-377 (average, 360) mm. 



Geographical distribution. — Coasts of western and northwestern 

 Austraha. Resident, south to southwestern Western Austraha, and 

 north to the western part of the Northern Territory (Melville Island). 

 ; This form I have not been able to examine, but judging from the 

 descriptions and measurements given by Mr. Mathews * and Mr. 

 Stresemann,^ it is a valid subspecies. Birds from Melville Island in 

 the Northern Territory of Australia, though close in geographical 

 position to the range of Thalasseus hergii pelecanoides, are apparently 

 much nearer Thalasseus hergii gwendolenae, at least in so far as their 

 size is concerned, and probably are best referred to the latter, as 

 already indicated by Mr. Stresemarm,* notwithstanding their north- 

 ern locality, which is, as a matter of fact, not so very far beyond the 

 northern part of Western Australia, whence come other examples of 

 Thalasseus hergii gwendolenae. The wings of five specimens from 

 Melville Island, as given by Mr. Stresemann, range from 346 to 365 

 mm., with an average of 357 mm. 



1 Used in measurement averages on p. 525. 



2 Eight specimens, from Western Australia, measured by Stresemann. 



'Novit. Zool., vol. 18,Jan. 31,1912, p. 208; Birds of Australia, vol. 2, pt. 3, Sept. 20, 1912, p. 347. 

 « Novit. Zool., vol. 21, Feb. 25, 1914, p. 59. 



