NATATORES. 399 



crown ; rump, upper tail-coverts, and tail white, except the 

 outer feathers of the latter, which are washed with grey. This 

 bird nearly resembles the S. cassinii of the Falkland Islands ; 

 but differs in its darker colouring and its much smaller size. 



The specific term melanorhpicha applied to the young of this 

 species being a very inappropriate designation for a bird which 

 in its adult state has a red bill, I would therefore suggest 

 that it be called Sancti-pauli. 



An egg of this species, sent by Mr. Macgillivray from St. 

 Paul's Island, is very like some of the dark varieties of the 

 Common Tern of Britain {Sterna Jdrundo). The ground colour 

 being olive-brown, blotched and marked all over, but parti- 

 cularly at the larger end, with rich umber, intermingled with 

 obscure markings of grey, the latter appearing as if beneath 

 the sui-face of the shell. The length is If inch, the breadth If. 



The sexes do not differ from each other in external appear- 

 ance. 



Eorehead, lores, sides of the neck, and all the under surface 



' white ; space surrounding the eye, occiput, and back of the 



neck black ; all the upper surface, wings, and tail delicate 



grey ; outer web of the external quill greyish black ; shafts of 



all the primaries white ; irides blackish brown ; bill black. 



Total length 13 inches ; bill 2^ ; wing 9f ; tail (d\ ; tarsi f . 



Sp. 605. STERNA GRACILIS, Gould. 



Graceful Tern. 



Sterna gracilis, Gould, Birds of Australia, fol., vol. vii. pi. 27. 



This graceful and elegant Tern was killed by Gilbert on 

 the Houtmann's Abrolhos, off the western coast of Australia, 

 where he states it is very numerous, continually moving about 

 from one part of those islands to another, and settling during 

 the heat of the day on the coral ridges in large flocks. He 

 was informed that it breeds there in great numbers during 

 the month of November, but he was unfortunately too late to 



