294 



COLYMBUS ARCTICUS. THE BLACK-THROATED 



LOON. 



BLACK-THKOATED DIVER. 



Colymbus arcticus. Linn. Syst. Nat. I. 221. 

 Colymbus arcticus. Lath. lad. Ornith. II. 800. 

 Black-throated Diver. Mont. Ornith. Diet. 

 ; Plongeon Lumme. Colymbus arcticus. Temm. Man. d'Ornith. II. 913. 

 Black-throated Diver. Colymbus arcticus. Selby, Illustr. II. 411. 

 Colymbus arcticus. Jenyns. Brit. Vert. Anim. 256. 

 Colymbus arcticus. Bonap. Comp. List. 65. 



Adult about two feet eight inches long ; with the hill black, 

 straight, two inches and a half along the ridge, tico-tliirds of 

 an inch in height at the base, icith the sides prominent, the 

 edges in -part involute, but direct at the base and toivard the 

 end ; the upper part of the head and the hind neck light-grey, 

 the fore part and sides of the head darker / the fore neck pur- 

 plish-black, ending angidarly below, and having a transverse 

 interrupted white hand above ; sides and loiver part of the neck 

 in front dusky, streaked tvith ichite ; the upper parts black, 

 glossed tvith green anteriorly, and shaded tvith hroivn behind ; 

 tivo dorsal bands of ivhite square spots in transverse rows ; sca- 

 pulars with larger white spots ,- the lower parts of the body 

 white, with a longitudinal dusky hand on the sides. 



Male in Summer. — This species lias the same general 

 form as the last, its body being elongated, rather slender, and 

 much depressed ; the neck long and rather thick ; the head of 

 moderate size, oblong, and anteriorly narrowed. The bill is 

 about as long as the head, straight, stout, compressed, taper- 

 ing, and pointed ; the upper mandible with the dorsal line 

 almost straight and direct, the ridge convex, the sides convex 

 beyond the nostrils, the edges involute for half their length 



