540 LARUS FUSCUS. 



The fore part and middle of the back, the scapulars, upper 

 Aving-coverts, and secondary quills are dark purplish-grey, or 

 blackish-grey with a purple tinge. The primaries and their 

 coverts are darker, their shafts black above, white beneath ; 

 all the quills tipped with white, the inner more largely, the 

 outer two very obscurely. 



Female. — The female is similar to the male in colour, 

 but somewhat smaller. 



Length to end of tail 21 inches ; extent of wings 54 ; 

 wing from flexure 17^ ; tail 6 ; bill along the ridge ^-J^, 

 along the edge of lower mandible 2y\ ; bare part of tibia 1-^ ; 

 tarsus 2^; first toe -f^, its claw -^ ; second toe Ij'y, its 

 claw ^; third toe 1-L^, its claw -^; fourth toe 1-f^, its 

 claw -^. 



Variations. — Excepting slightly as to size, individuals 

 vary little. The colour of the dark plumage changes when 

 old to a much lighter tint, approaching to deep leaden-grey. 

 Some individuals have a Avhite spot on the first, others on the 

 first and second primaries, and one which I shot on the Frith 

 of Forth has none. 



Male in Summer. — From April to October, there are no 

 streaks on the head and neck, but otherwise the plumage is 

 as in winter. The bill is of richer tint, or light orange, with 

 the patch on the lower mandible, the edges of the mouth and 

 eyes, vermilion, and the feet rich yellow. 



Length to end of tail 22^ inches ; extent of Avings 55 ; 

 wing from flexure 17-|^; tail 6^; bill along the ridge 2^, 

 along the edge of lower mandible 3-1-, its height ^ ; tarsus 

 2i ; first toe -fj, its claw -fj ; second toe 1-^, its claw -^ ; 

 third toe 1|^, its claw -^ ; fourth toe IfV? its claw ^. 



The dimensions of another male : — Length 22 ; bill along 

 the ridge 2f , along the edge of lower mandible 3-^, its height 

 •| ; tarsus 2^ ; middle toe and claw 2jy. 



The males described above were shot near Nortli BerAvick 

 in the end of .June 1824 ; a female, twenty-one inches in 

 length, was killed by myself, at Prestonpans, in 18o(). 



