176 



Trumbull on the Scoters. 



PAuk 



LApril 



swollen noticeably at sides of base between corner of mouth and nostril, 

 the bill differing in this respect from those of deglandi and stejnegeri. 

 Though an approximation to this protuberance is sometimes observable 

 in the other species, it is never so prominent and bunch-like. Lateral 

 edges of maxilla somewhat more nearly parallel than in deglandi, and 

 about as in stejnegeri. Basal part of culmen noticeably elevated, but not 

 nearly so prominently as in deglandi, and incomparably less than in 

 stejnegeri, rising very gradually and evenly over the nostrils. Anterior 

 extremities' of frontal and loral feathering (in both male and female) 

 about equally advanced. 1 



Oidemia stejnegeri. 



Average distance between nostril and loral feathering, — at nearest 

 point, — in both male and female, a trifle greater than in deglandi. Frontal 

 feathering seldom, perhaps never, advanced so far forward as the loral. 

 Knob enormously developed — over once and a half as high above nostrils 

 as the highest knob of deglandi, its abruptly rising front decidedly con- 

 cave, the top jutting forward suddenly and forming an overhanging, very 

 conspicuous, bluntly pointed projection ; the culmen somewhat higher at 

 the top of this overhanging portion than at frontal feathers. 



The knobs vary greatly even among drakes which at first sight are 

 seemingly mature. Closer inspection shows us that when the front of the 

 knob is not deeply concave, the bird is not fully developed, the basal 

 black is continued far forward, shows more or less all along the lateral 

 edges; and in positive lines running from the black in front of the nostrils 

 to the sides of the nail. (See fig. 8 in which similar lines are indicated 

 for deglandi.) On the other hand, when the front face of the knob is 

 deeply concave and its top juts conspicuously to the front, the bill is 

 broadly light, the black lines are absent (or very faintly and brokenly 

 indicated), the black is pushed but a short distance in front of the nostrils, 

 and shows but slightly along the lateral edges. Probably none of the 

 color is at all as it looked in life, but the black marking is distinct enough 

 fully to support what I have said. 



Though the bill passes through innumerable shapes while developing 

 from that of early youth, the culminal line of which is similar to that of 

 fig. 1, none of its late phases closely resemble any of those exhibited by 

 deglandi. 



1 I am unable to judge in the case of these bills in regard to the original amount Of 

 black and its distribution, as they have been artificially colored. Though the artist 

 who did the work is peculiarly accurate, he was forced to obtain his knowledge of the 

 coloration from very unsatisfactory pictures and descriptions. 



