500 LARID^i. 



rich black, the feathers of that colour on the occiput elon- 

 gated ; lower part of the neck, all round, white ; the back, 

 and all the upper surface of the body, the wings and tail- 

 feathers ash grey ; the first six wing-primaries of a much 

 darker grey, a slate grey, with white shafts ; the tail but 

 slightly forked ; the clnji, throat, breast, and all the under 

 surface of the body pure white; legs, toes, their mem- 

 branes, and the claws black, the latter strong and curved. 



The whole length of the specimen described, from the 

 point of the beak to the end of the long feathers of the 

 tail, is nineteen inches ; some specimens measure twenty to 

 twenty-one inches. Among the Terns the males are rather 

 larger than the females. From the carpal joint of the 

 wing to the end of the first, which is the longest, quill- 

 feather, seventeen inches and a half, the ends of the wings 

 extending considerably beyond the ends of the forked 

 feathers forming the tail. 



Young birds of the year, before their first autumn moult, 

 have the beak of a dull red, with some black at the point ; 

 the forehead and top of the head white ; the upper surface 

 of the body varied with patches of ash brown, and darker 

 transverse bands ; the feathers of the tail have dark ends ; 

 the primary quill -feathers are also dark; all the under 

 surface of the body pure white. 



Adult birds in winter have the head white, with a few 

 dark feathers behind the ear-coverts ; in all other respects 

 adult birds in winter resemble adult birds in summer, the 

 black head alone excepted. 



