ALCID.E — THE AUKS — ALCA. 



473 



Aha batlhica, BRUNN. Oin. Bor. 1764, 25, no. 101 (immature, without white line from bill to eye). 



Aha unisuhala, BkUsn. t. c. no. 102 (young). 



Alca glacialis, Bkehm, Vog. Deutschl. 1S31, 1004. 



Aha islaudica, Bhf.hm, t. u. 1005. 



Aha microrhynchw, Breiim, Vogelf. 1S55, 410. 



Hab. Coasts and islands of the North Atlantic, down to about latitude 40° in winter. Japan ? 

 {fide Schlkgel). 



ecs more 

 and fore- 



A. tarda. 



Sp. Char. Adult, in summer: Head, neck, and upper parts black, the hea< 



fuliginous, and changing to soft, velvety snuff-brown on the under portion of ll 

 neck ; secondaries narrowly tipped with white ; 

 a narrow white line running from the base of 



the culnien to the eye. Lower parts, including ,^. "* -»- 



jugulum, axillars, and lining of the wing, im- 

 maculate white. Bill black, botli mandibles 

 crossed about the middle by a white line ; 

 "inside of mouth gamboge-yellow; iris deep 

 hazel ; feet black " (Audubon). Adidf. in 

 winter : Whole under portion of the head, tore- 

 neck, and post-auricular region white ; no white 

 line from eye to bill ; bill without basal lam- 

 ina. Otherwise like the summer plumage. 

 Young : Similar to the winter plumage, but 

 bill smaller, perfectly smooth, and without tin 

 white bar across the middle portion. 



Total length, about 17.00 inches ; wing, 

 8.00 to 8.50; tail, 3.50 ; culnien, 1.25; great- 

 est depth of bill, .90 ; tarsus, 1.25 ; middle 

 toe, 1.55. Summer adult. 



This is a northern and Arctic species, abundant throughout the eastern shores of 

 North America from the highest latitudes to Maine in summer and to New Jersey in 



VOL. II. — 00 



