53« LARUS MARINUS. 



fvom the Bass Rock, in the end of June 1824, hy Mr. 

 l)e Jersey. 



Progress to^vard Maturity. — After the first autumnal 

 moult, the colours are as follows : — 



Young in the First Winter. — The bill is bluish- 

 black, the extreme tips and a small portion of the base of 

 the lower mandible dusky yellowish-grey ; the iris and edges 

 of the eyelids brown ; the feet flesh-coloured, tinged with 

 ])ale blue, about the tibio-tarsal joint inclining to verdigris- 

 green ; the claAVS blackish-broAvn. The head is light grey, 

 streaked with pale brown ; the throat greyish-white. The 

 back is confusedly mottled with hair-brown, on a broAvnish- 

 white ground, tinged with yellow^, in patches increasing in 

 size and depth of tint backAvards ; the wings mottled in the 

 same manner, but the brown deeper ; the primaries, primary 

 coverts, and secondaries blackish-brown, narrowly tipped 

 with greyish-white. The arrangement of the dark colour on 

 the back is in single spots on each feather, as is also the case 

 on the Aving-coverts ; but the secondary coverts have the 

 inner webs broAvn, with processes to the number of four 

 shooting into the light colour of the outer webs, the intervals 

 ash-grey. The bases of the feathers of the back are pale 

 ash ; their edges and tips brownisli-Avhite. On the rump 

 and tail-coverts white predominates. The tail-feathers are 

 white at the base, brownish-black toward the end, tipped 

 with white ; the middle feathers barred Avitli broAvn for two- 

 thirds, the outer white until near the end. The loAver parts 

 are whitish, tinged with grey and yellow, and marked a\ ith 

 very pale brown spots ; the lower Aving-coverts mottled Avith 

 broAvnish-grey and pale broAvn ; the axillar feathers broAvnish- 

 grey, barred Avith pale broAvn. 



Second Winter. — Bill deep broAvn, tinged Avith blue 

 toward the end, the tips yelloAvish-grey ; the base, especially 

 of the loAver mandible, yellowish, tinged Avith broAvn ; the 

 basal margin of the mouth and the bare edges of the eyelids 

 yellowish ; the feet more decidedly flesh-coloured. The fore 



