ALCIDiE — THE AUKS — SIMOUIIYNCIIUIl;. 



513 



color of bill dull brownish. Youmj (= Uria (hibin, Pallas) : Dill simple and smooth as in the 

 winter adult, but smaller ; plumage as in the lulult, but ci-est and auricular tiLimcnts absent or but 



he 



he 

 hrt 



.1; 



Summer adult. 



slightly developed. Bill dull brownish. Total length, about 0.00 inches ; wing, 6.25 ; culmen, 

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



Juflging 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 during the latter part of their 



il 



Winter aditll. 



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

 ing-season. Perfectly adult binls apparently retain its perimncnt ornaments the curled frontal 

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

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

 VOL. II. — 65 



