528 LARID.E. 



I believe this to be the first record of the occurrence of this 

 bird in Britain, I subjoin a short description of the speci- 

 men and a sketch half the natural size, to assist in drawing 

 the attention of British naturalists to it, as it will probably 

 be found not unfrequent. 



" Measurement. Total length, to extremity of tail, 

 about eight inches ; bill from base ten lines and a half, 

 from rictus one inch five lines ; greatest depth of both 

 mandibles two lines and a half ; middle toe, including the 

 claw, eleven lines in length ; tarsus eight lines ; naked 

 portion of the tibia four lines. Colours. Legs and feet in 

 the preserved specimen pale yellow, probably red in the 

 living bird, claws darker ; bill dark blackish-brown ; head, 

 neck, breast, abdomen, under wing-coverts, and back deep 

 glossy black ; small wing-coverts, tail, and upper and 

 under tail-coverts pure white ; first three quill-feathers 

 black, with a broad longitudinal band of white on the inner 

 webs; remainder of the wings ash-grey, becoming darker 

 towards the body. 



" The form, proportions, and size of this species are very 

 nearly those of the Black Tern, S. nigra ; like that species, 

 too, the webs of the toes are very deeply indented, being 

 reduced to a mere rudiment between the middle and inner 

 toes. The two species are however easily distinguished, 

 the under wing-coverts of the $. nigra are white, of the 

 S. leucoptera black ; the tail of the former is dark grey, 

 of the latter pure white ; in the S. nigra the throat is 

 white, breast and abdomen dark grey, and the back lead- 

 colour, while in the S. leucoptera all those parts are black. 

 I speak of both species in their perfect plumage." 



M. Temminck says, " this White-winged Tern inhabits 

 the bays and inlets of the shores of the Mediterranean, and 

 is very common about Gibraltar ; it visits also the lakes, 



