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NEW YORK STATE MUSEUM 



does not project as in Mergus, though it is not an uncommon 

 thing to find it so even among true ducks. 



Lophodytes cucullatus has a sternum of the same 

 general pattern as the bone I have just described for Mergus. 

 Posteriorly, however, it is proportionately more flaring or wider, 

 while the keel is carried back farther, and the mid xiphoidal pro- 

 jection is not so strongly developed. At the forepart of the bone, 

 the carina is not nearly so far extended to the front as it is in Mer- 

 gus, and the coracoid processes are more acute. It is nonpneu- 

 matic as is the bone in other Merginae. In some respects the ster- 

 num of Lophodytes is more like the sternum of Clangula than 



Fig. 5 Left scapula and coracoid of Mergus serrator, with furcula detached. 

 Natural size. Drawn by the author from specimen no. 16626, United States National 

 Museum Collection. (Compare figures 1-4) 



is the sternum of Mergus, particularly in the matter of the keel 

 not being so far produced in front. 



Shoulder girdle [fig. 5]. Most ducks, and T believe all the mer- 

 gansers, have a nonpneumatic pectoral arch. It is the case in our 

 present subject, and in a number of the former at my hand, as it 

 is also in Lophodytes. 



The furcula typifies the broad U-arch in Mergus, where the 

 curve is continuous and unchecked by the presence of a hypo- 

 cleidium. 



The bone is, as a whole, slightly curved backward, so each limb 

 presents a convexity to the front ; these become broader and later- 

 ally compressed as we pass in the direction of their free extremities. 



