C0LY2IBID2E: LOONS. 791 



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

 quatus, but smaller; color lilack. Cliiu, tliroat, and ueclc in front, black, with purplish ami 

 violet rcttectious on tlie sides of the head, ji-radually fading into a fine, clear bluish-gray, deep- 

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

 streaks. A crescent of short, wliite streaks across upper throat; sides of breast .striped with 

 pure white and glossy black, these stiipes nearly meeting in fi-ont. Entire upper parts deep, 

 glossy greenish-black, each feather of scayjulars and interscapulars with a white spot near end 

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

 ooverts thickly speckled with small ovate wldte spots. Inner webs of quills, and tail-feathers 

 below, light grayish-brown. Sides under x\-ings liiie back. Lining of wings and entire under 

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

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

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

 dull grayish-\vhite, 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 

 dusl;y margined with gray. Fore-part of neck grayish -white, minutely and faintly dotted witli 

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

 wing 12.00; bill along culmen 2.i.5 ; along gape 3.40; its height at nostrils 0.6.5; its width 

 there 0.35 ; tarsus 2.90; outer toe and claw 3. SO. X. Hemisphere ; not common iu the U. S. 



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

 last; colors the same. Size less; length 2i.OO; wing 11.00. Bill shorter, slenderer, somewhat 

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

 occidentalis and JE. clttrhi. Bill along culmen 1.00-2.20; 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. septentrioncdis, 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 ra\ni nearly straight ; gonys slightly 

 convex. Frontal antife scarcely extending bej'ond 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 

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

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

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

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

 aries blackish, paler on the inner widjs. Tail narrowly tipped with wliite. Under parts and 

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

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

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

 whitish. Entire upjier 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 



