BONAPARTE'S GULL. 135 



The female is somewhat smaller, and resembles the male, but has the head 

 and upper part of the neck umber-brown. 



Young in December. 



Bill greyish-black, iris dark brown; feet flesh-coloured, claws dusky. 

 Head and neck greyish-white; a small black patch about an inch behind the 

 eye on each side. Upper parts dull bluish-grey, many of the wing-coverts 

 greyish-brown, edged with paler; quills as in the adult; rump and tail white, 

 the latter with a broad band of black at the end, the tips narrowly edged 

 with whitish. 



Length to end of tail 13|-, to end of wings 15-§, to end of claws 13; 

 extent of wings 32^ inches. Weight 6 oz. 



The white spots on the tips of the wings vary greatly in size, and are 

 frequently obliterated when the feathers become worn. 



Palate with five series of small distant papillae. Tongue 1 inch 1|- twelfths 

 long, slender, tapering to a slit point, emarginate and papillate at the base, 

 horny towards the end. Aperture of posterior nares linear, 9 twelfths long. 

 Heart 1 inch long, 9 twelfths broad. Right lobe of liver 1 inch 11 twelfths 

 long, the other lobe 1 inch 7 twelfths. 



The oesophagus is 6^- inches long, very wide, with rather thin parietes, its 

 average diameter when dilated 10 twelfths, within the thorax enlarged to 1 

 inch 2 twelfths. The transverse muscular fibres are distinct, the internal 

 longitudinal less so; the mucous coat longitudinally plicate. The proven- 

 triculus is ^ inch long, with very numerous small glandules. The stomach 

 is a small oblong gizzard, 10 twelfths long, 8 twelfths broad; its lateral 

 muscles rather large, as are its tendons. The inner coat or epithelium is of 

 moderate thickness, dense, with nine longitudinal broad rugae, and of a 

 brownish-red colour. The intestine is 24^ inches long, its diameter 2 

 twelfths. The rectum is 1^ inches long. The cceca are 2 twelfths long, 

 1 twelfth in diameter, cylindrical and obtuse. 



The intestine of another individual, a male, is 20|- inches long, 3 twelfths 

 in diameter. 



The trachea is 3 inches 10 twelfths long, its diameter at the top 3 twelfths, 

 at the lower part 2\ twelfths, the rings very feeble, unossified, about 130 in 

 number. The sterno-tracheal muscles are very slender, as are the contrac- 

 tors; and there is a pair of inferior laryngeals. The bronchi are of mode- 

 rate length, with about 18 half rings. 



