4IO PATAGONIAN EXPEDITIONS : ZOOLOGY. 



extends backward surrounding the eye and, joining behind it, extends 

 backward almost to the median line of the nape. The chin and base of 



Fig. 2 1 6. 



Cygnus melanocoryphus 7858, P. U. O. C. Profile of head and bill from above. Greatly 

 reduced. 



lower mandible are frequently defined by a narrow white area (see Fig. 

 216). 



Neck : Entirely velvety black, except for its posterior few (4) inches, 

 where it becomes abruptly pure white. 



Back: White. 



Tail : White. 



Wings : White. 



Entire lower parts, except anterior lower neck as described, white. 



Iris : Dark brown. 



Bill : "Plumbeous with base and knob red" (Natterer). 



Feet: "Brownish flesh color" (Colburn). 



The adult female does not differ from the adult male in color. (Adult 

 female cited above.) 



Immature birds lack the frontal knob on the bill. The head and neck 

 are dull brownish black, much lighter than in the adult. The white 

 feathers of the upper parts and the wings and tail are more or less marked 

 with dull greyish rusty brown, which color prevails on the tips of the 

 primary quills. The lower parts are also marked in a less degree with 

 dull rusty brown. 



Downy birds are greyish white. 



Geographical Range. — Southern Brazil, Paraguay, Uruguay and thence 

 south through Argentina, Chili and Patagonia to the Falkland Islands. 



