COLYMBIDJE: LOONS. 791 



842. C. arc'ticus. (Lat. arcticus, arctic.) Black-throated Diver. Bill generally as iu tor- 

 quatxs, but smaller; color blade. Chin, throat, and neck in front, black, with purplish and 

 violet retlectioiis on tlie sides of the head, gradually fading into a tine, clear bluish-gray, deep- 

 est on foreheail, lightest behind, and separated from the black of the throat by a series of white 

 streaks. A crescent of sliort, wiiito streaks across upper throat; sides of breast striped with 

 pure white and glossy black, these stripes nearly meeting in front. Entire upper parts deep, 

 glossy groonisli- black, each feather of scapulars and interscapulars with a white spot near end 

 of each wob; those of tiie scapulars largest, forming four patches in tranverse rows. Wing- 

 coverts thickly speckled witii small ovate white spots. Inner webs of quills, and tail-feathers 

 below, light grayish-brown. Sides under wings like back. Lining of wings and entire under 

 parts from the neck, pure white, with a narrow dusky band across lower belly; under tail- 

 coverts dusky, tipped with white. Young : Bill light bluish-gray, dusky along the ridge. 

 Iris brown. Feet dusky. Upper part of head and neck dark grayish-brown ; sides of head 

 duU grayish-white, minutely streaked with brown. Upper parts with a reticulated or scaly 

 appearance, the feathers being brownish-black with broad bluish-gray margins; the rump 

 dull brownish-gray. Primaries and their coverts brownish-black ; secondaries and tail-feathers 

 dusky margined with gray. Fore-part of neck grayish-white, minutely and faintly dotted with 

 brown ; its sides below streaked with the same. Lower parts, including under surface of 

 wings, pure white, the sides of the body and rump, with part of the lower tail-coverts, dusky, 

 edged with bluish-gray. (Audubon.) Dimensions: length about 30.00; extent 40.00; 

 wing 12.00; bill along culmen 2.45; along gape 3.40; its height at nostrils 0.65; its width 

 there 0.35 ; tarsus 2.90 ; outer toe and claw 3.80. N. Hemisphere ; not common iu the U. S. 



843. C. a. paci'fieus. (Lat. pacificiis, pacific.) Pacific Black-throated Diver. Like the 

 last; colors the same. Size less; length 24.00; wing 11.00. Bill shorter, slenderer, somewhat 

 differently shaped, with straight culmen — much like the difference between ^chmophorus 

 occidentalis and ^. clarki. Bill along culmen 1.90-2.20; gape 3.00; length of bill 0.50 or 

 less; tarsus about 2.50. N. W. America; abundant on Pacific coast of U. S. in winter. 



844. C. septentriona'lis. (Lat. septentrionalis, northern.) Red-throated Diver. Bill usually 

 slenderer than in the foregoing; culmen slightly concave at the nostrils, gently convex to tip, 

 which is rather obtuse and a little decurved. Outline of rami nearly straight ; gonys slightly 

 ccravex. Frontal antise scarcely extending beyond base of nostrils. Tarsus relatively rather 

 longer than in foregoing species, about four-fifths the middle toe. Adult: Bill black, rather 

 lighter at the tip. Crown and broad cervical stripe glossy greenish -black, the latter thickly 

 streaked with white, which streaks, on the sides of the breast, spread so as to nearly meet iu 

 front. Throat and sides of head clear bluish-gray. A large, well-defined, triangular, chest- 

 nut-brown throat-patch. Entire upper parts and sides under the wings deep bro\vnish-black, 

 with greenish gloss, everywhere profusely spotted with white, the spots small, oval. Prim- 

 aries blackish, paler on the inner webs. Tail narrowly tipped with white. Under parts and 

 lining of wings white, the axillars with narrow dusky shaft-streaks, and the lower belly, wuth 

 some of the under tail-coverts, dusky. Young : Bill mostly light bluish-white, with dusky 

 ridge. Crown of head and neck behind bluish-gray, the feathers of the former bordered with 

 whitish. Entire upper parts brownish- or grayish-black, everywhere profusely marked with 

 small oval and linear spots of white. Throat without red patch, its sides and those of the 

 head mottled with dusky. Other parts as in the adult. Length 25.00 ; extent 44.00 ; wing 

 11.00 or less; bill along culmen 2.00; along gape 3.00; height at nostril 0.50; width there 

 0.35 ; tarsus 2.75 ; outer toe 3.50. Varies greatly in size, and in the size and shape of the bill; 

 recognized by the profuse spotting of the upper parts, as well as, when adult, by the red throat- 

 patch. The spots are smallest and most numerous on the wing-coverts and upper back, where 

 they grade into the streaks of the hind neck ; largest on the tertials, scapulars, and sides under 

 the wings, where they are rather lines than spots, and are fewest, or almost wanting, on the 



