of the United States. 421 



Adult black, slightly marked with white, back unspotted ; 

 beneath white ; head brownish gray ; neck beneath glossy 

 black ; a stripe each side of the neck marked with white. 



Young ashy-brown, beneath white. 



Black-throated Diver, Edw. Glean, pi. 146- adult. Buff, 

 pi. enl. 914. young. 



Inhabits the arctic parts of both continents : very rare and 

 accidental during winter in the middle states : common in 

 Arctic America, as well as in some northern parts of Europe. 



370. Colymbus septentrionai.is, L, Bill three inches long, 

 slightly recurved ; edges much bent in ; lower mandible 

 channelled ; tail of twenty feathers. 



Adult blackish, beneath white, head and neck glossy cine- 

 reous ; neck beneath with a long reddish stripe. 



Young ashy-brown, spotted with white, beneath white. 



Red-throated Diver, Edw. Glean, pi. 97. adult. Buff. pi. 

 enl. 308. adult. 992. young. Colymbus septentrionalis, striatus, 

 stellatus, et borealis. auct. C. septentrionalis, Vieill. Gal. 

 des Ois. 282. adult. 



Inhabits the north of both continents: the young only com- 

 mon during winter in the middle states, as well as in Italy. 



B. Feet 3-toed. 



Brachypteri, Vieill. Alcce, Fraterculce, Boie. Ditichi, 

 Ranz. Alcadce, Vigors. 



85. URIA. 



Aha, Colymbus, L. Gm. Uria, Briss. 111. Temm. Ranz. 

 Uria, Alca, Lath. Cephus, Pallas. Uria, Cephus, Cuv. Uria, 

 Cephus, Mergulus, Boie. Uria, Mergulus, Vieill. Brehm. 



Bill moderate, slender, robust, smooth, straight, compres- 

 sed, acute, base feathered ; upper mandible convex, some- 

 what curved at the point, notched ; lower hardly shorter, 

 slightly navicular ; edges of both bent in, sharp : nostrils in 



Vol. II. 53 



