254 ^E\Y YORK STATE MUSEUM 



and not double that number of lines to the skull. Still these " Out- 

 lines " are of great value in other directions, and have been care- 

 fully consulted during the writing of that part of the present 

 paper which has especially to do with the Cygninae. 



Fossil Anseres have been found at various times in different 

 geological horizons. Some of these belonged to more or less true 

 anserine types now extinct; some were of forms only more or less 

 remotely allied to the Anseres; finally, many of them, especially in 

 the recent formations, are identical with swans, ducks, geese, and 

 mergansers, belonging to the existing avifauna.^ Chief among the 

 labors done in this direction are the memoirs of Sir Richard Owen, 

 of Gervais, and of W. K. Parker. 



The titles of a vast number of works relating to the Anseres are 

 to be found in the Ornithological Bibliograpliy of Coues, a volume 

 that has been freely consulted in the present connection. 



What I have now to say about the osteology of the Merginae, 

 will be based upon a study of the skeleton of Mergus ser- 

 rator, and taken from my memoir Observations upon the Oste- 

 ology of the North American Anseres, referred to above. In doing 

 this, however, I shall make some comparison with a skeleton of 

 Lophodytes cucullatus, and include these observations 

 with what was said in my earlier paper. 



Mergus serrator 



Skull. We find in this bird that the lamellae of the bill develop 

 toothlike serrations for the entire length of both mandibles. These 

 pseudoteeth, however, make no impression whatever upon the os- 

 seous base of the bill, and in a well prepared skeleton we would 

 never suspect their existence. This is equally true of Lophodytes. 

 Upon lateral view of this skull [fig. i] we see that the superior 

 mandible curves slightly upward as we proceed toward its apex ; 

 the lower margin is sharp, and above it is convex, except in the 

 craniofacial region and somewhat beyond, where it is depressed. 



The nasal is a large, broad bone; its anterior margin is rounded as 

 in other holorhinal birds. The nostril is elliptical and placed hori- 

 zontally, and the sutural traces of the bones that surround it en- 

 tirely obliterated. 



The lacrymal bone is triangular in form, its apex below terminat- 

 ing in a spindle-form process, which is curved somewhat outward. 



^ Sec Shufeldt, R. W. A Study of the Fossil Avifauna of the Equus Beds of the 

 Oregon Desert. Acad. Nat. Sci. Phila. Jour. 1892. 9:389-425, pi. 15-17. 



