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 Hapace Islands, which is the centre cluster of the three 
groups usually considered to form the Friendly or Tonga Islands. 
The bird of the Hapace Islands may, when made known, prove to 
be a species closely allied to the Megapodius Pritchardit, if not the 
same. 
On A New Species or Prionors. 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, ramp, 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 Retzi, but it is without the 
white rump, and the tips of the tail-feathers are white on both webs. 
DeEsCRIPTION OF A NEw SPECIES OF GULL FROM TIBET. 
By J. Goutp, Esa., 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 123 inches, tail 5 inches, 
tarsi 24 inches. 
Hab. Tibet. 
Remark. This fine and very distinct species belongs to that section 
of the Laride which comprises the well-known Black-headed Gull, 
