1878.] MR. H. SAUNDERS ON THE LARIN.E. 211 



men of this Gull should ever have been obtained in any part of 

 California ; and Mr. Salvin inclines to think the Californian locality 

 an erroneous one, in view of similar mistakes known to have been 

 made with the birds collected during the voyage of the 'Venus.' It 

 is on the other hand somewhat strange that if the head quarters of 

 this Gull, of which the appearance is sufficiently striking to attract 

 attention, are in the Galapagos group, none of the other visitors or 

 naturalists should have brought any news of it. 



Creagrus is one of Bonaparte's arbitrary and undefined genera ; and 

 there seems to be no structural difference to warrant the generic 

 separation of this species from Xema sabinii. 



In this paper I have from time to time acknowledged with much 

 pleasure the assistance I have received from my friends and cor- 

 respondents ; and I have now to render my especial thanks to the 

 authorities of the British and Cambridge Museums, and of the 

 Smithsonian Institution, Washington, and to Dr. Brewer of Boston, 

 to Professor Peters of Berlin, Professor Bernhardt of Copenhagen, 

 M. Oustalet, M. Bouvier, Mr. O. Salvin, Mr. H. Seebohm, Mr. 

 Harvie-Brown, Mr. Gervase Matthew, R.N., and Mr. E. Hargitt, 

 for the opportunities they have severally afforded me of examining 

 examples of rare species and also series of specimens. 



P.S. (April 1st). — I take this opportunity of correcting an error 

 in my paper on the Sternince (P. Z. S. 1876, p. 671) where two 

 species are united under the name of Anous cceruleus. At that 

 time I had not seen a specimen of the real A. cceruleus, Bennett; 

 and that species and A. cinereus, Gould, are so very much alike 

 that, until examples were available for comparison, the descriptions 

 and plates might easily have been taken to refer to the same species 

 in different stages of plumage. Seen by the light of further expe- 

 rience they appear to be distinct ; and the following is their synonymy 

 and habitat: — 



Anous cjeruleus (Bennett). 



Sterna cerulea, F. D. Bennett, Narr. Whaling-Voy. round Globe, 

 ii. App. p. 248 (1840), Christmas Island, Pacific. 



"Sterne cendre," Neboux, Rev. Zool. Oct. 1840, p. 291, et 



Stolida cinerea. id. Voy. 'Venus,' Atlas, pi. 9 (1846); nee Anous 

 cinereus, Gould, P. Z. S. 1845 (Pacific, N. of Equator). 



Sterna teretirostris, Lafresnaye, Rev. Zool. 1840, p. 242, et 



Procelster?ia tereticollis, id. Mag. de Zool. 1842, pi. 29 : no lo- 

 cality ; both described from a single specimen purchased from a 

 dealer at Havre. 



Anous parvulus, Gould, P. Z. S. 1845, p. 104 (described from a 

 specimen obtained by Bennett at Christmas Island) ; Cassin, U.S. 

 Expl. Exp., Birds, p. 393 (Honden Island, Low archip. 14° S., 

 138° W.). 



Megalopterus plumbeus, Peale, U.S. Expl. Exp. p. 285 (1S4S\, 

 Honden Island. 



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