of the United Stales. 429 



little. Chick at first covered with a very long down, much 

 longer than that of the adult. 



Live socially in Arctic seas, whence they migrate parti- 

 ally in winter : keeping near the shores and retiring at 

 night, and in stormy weather, to clefts or burrows. Swim 

 and dive admirably, to great depths : walk better than the 

 allied species. Flight short, skimming the water, assisting 

 it by striking the surface with their feet, rarely a little eleva- 

 ted. Feed on Crustacea, mollusca, and other small marine 

 animals, with a few sea-weeds, cutting their food with their 

 bill before swallowing it. Build in great numbers on cliffs, 

 generally digging burrows with their bill and claws in the 

 earth collected in the cavities of rocks ; lay a single hard- 

 shelled egg, of greatly disproportioned size. Very affection- 

 ate parents, fighting boldly in defence of their young. Seen 

 flying among the rocks only when carrying them food in 

 their bill. 



Confined to the most northern latitudes throughout the 

 globe. Species well ascertained, only our three. 



378. Mormon cirrhatus, Tcmm. Blackish, quill shafts white ; 

 eye-brows white, posteriorly cirrhated ; bill moderately com- 

 pressed, furnished at base with an osseous sheath, upper man- 

 dible only grooved. 



Young, bill smooth, no ornaments. 



Tufted Auk, Alca cirrhata, Lath. Buff. pi. enl. 761. Fra- 

 tercula cirrhata, Vieill. Gal. 296. adult. Omitted in my 

 Catalogue. 



Inhabits the sea between North America and Kamtschatka, 

 often seen on the western coasts of the United States in winter. 

 Appears to come nearest to Cerorhinca, by the sheath of its 

 bill only differing in shape from that of that singular bird. 



379. Mormon glacialis, Leach. Black, beneath white, abroad 

 black collar ; bill exceedingly high, moderately compressed, 

 both mandibles with at most two grooves before the nostrils, 

 lower extremely curved. 



Vol. II. 54 



