184 BIRDS OF ILLINOIS. 



one against the lateral base of the bill, the other over the auriculars, behind and below 

 the eye; plumage above, more uniform than in the adult female, and feathers every- 

 where of a softer texture. 



Total length, about 19.00-20.00 inches; extent, 31.00-34.00; wing, 9.25-9.75; culmen, 1.30-1.60; 

 from tip of bill to lateral base. 2.35-2.60; distance through base of bill horizontally, be- 

 tween most prominent point of lateral swellings, 1.10-1.40; tarsus, 1.55-1.85; middle toe. 

 2.15-2.55 (twenty examples). 



The handsome Surf-Duck is also a winter visitant to Illinois, 

 where, according to Professor Cooke, it occurs on all the larger 

 streams, as well as on Lake Michigan. Mr. Nelson records it 

 as numerous on the Calumet marshes, during the fall and winter 

 of 1875, where it arrived the last of October and remained 

 until toward the end of March. 



The following summary of its habits is given by Col. N. S. 

 Goss, in The Auk, for April, 1889, p. 123: 



"This species of sea duck is abundant upon both coasts, and 

 during the breeding season is quite common upon the large 

 northern inland waters; breeding from Sitka, Alaska, and the 

 Gulf of St. Lawrence north to the Arctic coast. Its food consists 

 largely of shell-fish (the mussel is a favorite, the shells of which 

 appear to digest as easily as the animal within them) and 

 fishes, and various forms of life also help to make up the bill 

 of fare. Its flesh is coarse, and rather rank in flavor. The 

 birds are at home as well in the surging surf as upon the 

 smoother waters, resting and sleeping at night far out from 

 the shore. They rise from the surface in a running, laborious 

 manner, but when fairly on the wing fly rapidly, and in stormy 

 weather hug close to the water. While feeding they are very 

 active, constantly and rapidly diving, one after the other, con- 

 tinually disappearing and popping up." 



Genus ERISMATURA Bonapakte. 



Oxyura Boxap. Synop. 1828, 390. Type Anas rubida Wils. (Sec Oxyurus Swains. 



1827). 

 Erismatura Bonap. Saggio. Distr. Met. 1832, 143. Same type. 

 Gymnura Nutt. Man. ii, 1834, 426. Same type. 

 Undina Gould, Birds Eur. v, 1836. pi. 383. Type. Anas mersa Pall,= .4. leucocephala 



Scop. 



Cerconecles Wagl. IsK 1832,282. Type, A. leucocephala Scop. 



Bythonessa Glog. Handb. 1842. 472. Type, A. leucocephala Scop. 



Gen. Chab. Bill about as long as the head (much longer than the tarsus), very broad, 

 widened toward the end, elevated at the base, the nostrils very small, and situated very 

 near the culmen; maxillary unguis very small, narrow, and linear, the terminal half bent 



