610 



GAVIA BONAPARTII. BONAPARTE'S MEW. 



BONAPARTUN GULL. 



Larus Bonapartii. Bonapartian Gull. Eicharda. and Swains. Fauna Bor. 



Amcr. II. 425. 



Bonapartian GuU. Larus Bonapartii. Aud. Omith. Biogr. IV. 212. 



Bonapartian Gull. Larus Bonapartii. Thomps. Nat. Hist, of Ireland, 



in. 317. 



Bill an inch and a third in length, slender, hlach; tarsus 

 an inch and a third; feet red ; wings an inch and three- 

 fourths longer than the tail, which is even at the end ; outer 

 xoeb of first quill hlach, of the next three white. In summer, 

 the back and wings light bluish-grey ; the lower parts and tail 

 tohite ; the head and throat greyish-black ; the female brown. 



Mr. Thompson announced, in 1848, the capture of an 

 individual of this species at Belfast, and at the same time 

 gave a very minute description of it. The following, how- 

 ever, is taken from American specimens : — 



Male in Summer. — Of smaller size and more slender 

 form than Xema ridibunda. Head rather small, ovate- 

 oblong, narrowed and compressed anteriorly. Bill shorter 

 than the head, nearly straight, slender, compressed. Upper 

 mandible with its dorsal outline straight for half its length, 

 then gently arcuato-declinate, the ridge narrow, the edges 

 sharp and somewhat inflected, the tip narrow, with slight 

 notches. Lower mandible with the angle long and very 

 narrow, the prominence slight, the dorsal line ascending and 

 slightly concave, the tip acute. Nostrils linear, pervious, 

 rather more than a quarter of an inch in length. Legs 

 rather short ; tibia bare for eight-twelfths of an inch ; tarsus 



