ALCID/E — THE AUKS — SIMORHYNCHUS. 



513 



color of bill dull brownish. Youvrj (= Uria chibia, Pallas) : Bill simple and smooth as in the 

 winter adult, but smaller ; plumage as in the adult, but crest and auricular filaments absent or but 



Summer adult. 



slightly developed. Bill dull brownish. Total length, about 9.00 inches ; wing, 5.25 ; culmen, 

 .45 ; tarsus, 1.00 ; middle toe, with claw, 1.35. 



Judging from the very extensive series of specimens before us, it appears that the young gradu- 

 ally assume both the frontal crest and the white auricular filaments dujing the latter part of their 



;^^^^,^^^^^^^^fc£^?s^ci^=!i^^ 





Winter adult. 



first year, the peculiar character of the bill being gradually assumed at the approach of the breed- 

 ing-season. Perfectly adult birds apparently retain as permanent ornaments the curled frontal 

 crest and line of white acicular feathers across the auricular region ; but after the close of the 

 breeding-season the basal horny parts of the bill (perhaps also of tlie entire bill, since the terminal 

 VOL. ir. — 65 



