Mr. J. Gould on a new Gull from Tibet. 379 



The natives of the Tonga Islands informed Mr. Pritchard that the 

 bird was " not found on any of their islands, except Nina Fou." 

 There is, however, in the British Museum an egg, with the provi- 

 sional name of Megapodius Burnabyi, which agrees with the de- 

 scription of the Nina Fou egg. It was obtained by Lieut. Burnaby, 

 R.N., at the Ilapace Islands, which is the centre cluster of the three 

 groups usually considered to form the Friendly or Tonga Islands. 

 The bird of the Ilapace Islands may, when made known, prove to 

 be a species closely allied to the Megapodiut Pritchardii, if not the 

 same. 



On a New Species or Prionops. By G. R. Gray. 



I beg to lay before the Meeting the description of a new species 

 of Prionops, which has been obtained during the Zambesi expedition. 



Prionops tricolor. 



Black ; back, rump, wing-coverts, and tertials purplish grey ; quills 

 fuscous black, from the second to the tenth quills crossed interiorly 

 with a white oblique band ; vent, under tail-coverts, and tips of the 

 tail-feathers white ; on the latter the white decreases in width from 

 the outer to the central feathers, where it exhibits only a small spot 

 on each feather. 



The frontal plumes covering the nostrils are short, turned upwards, 

 and slightly curved backwards in front of the eyes, like those of the 

 Prionops Talacoma, which latter species, with the new one, were sent 

 in the first series of birds as from Tette. 



The eyes are surrounded by serrated fleshy rings. The bill and 

 feet red ; the former is tipped with yellow. 



Length 7" 6'" ; wings 5^'. 



This new species is allied to Prionops Retzii, but it is without the 

 white rump, and the tips of the tail-feathers are white on both webs. 



Description of a New Species of Gull from Tibet. 

 By J. Gould, Esq., F.R.S., etc. 



Chroicocephalus tibetanus, Gould. 



Head light chocolate-brown, deepening into black on the nape, sides 

 of the head, and fore part of the neck ; back and wings delicate grey; 

 shoulders and edge of the wing pure white ; first two primaries 

 black, with an oblong patch of white occupying the basal portion of 

 the outer web and the corresponding portion of the inner web for 

 about half its breadth, and with an oval patch of white near the tip ; 

 the remaining quills white, largely tipped and broadly margined along 

 the inner web with black ; remainder of the plumage, comprising the 

 neck, under surface, upper and under tail-coverts, pure white ; bill, 

 legs, and feet coral-red ; nails black. 



Total length 16 inches, bill 2 inches, wing 1 2| inches, tail 5 inches, 

 tarsi 2| inches. 



Hab. Tibet. 



Remark. This fine and very distinct species belongs to that section 

 of the Laridte which comprises the well-known Black-headed Gull, 



