52 NEW YORK STATE MUSEUM 



second, third and fourth segments measure 1.8, 1.4, 1.1 and 1.6 centi- 

 meters, respectively; in Neophron the same segments measure, in 

 the same order, 1,2, .5, .4, and 1.5 centimeters. 



A number of the characters which I have pointed out as being 

 found in the skeletons of the Cathartidae will probably be touched 

 upon again, when the osteology of the American genera of the 

 Falconidae is reviewed. To this subject we will now at once pass, 

 and at its close, a complete, though brief, synopsis of the skeletal 

 characters of the Accipitres will be presented, together with a few 

 remarks in reference to some of their affinities. 



FALCONIDAE 



As an introduction to a study of the skeletology of this family, 

 as it is represented in our United States avifauna, I will here re- 

 publish my account of the osteology of Circus hudsonius 

 and in the remainder of this treatise compare the characters of the 

 skeleton of this harrier with such other skeletons as are at hand 

 representing the hawks, eagles, kites and others. By such a 

 method it will be quite possible to very fully present all of the more 

 important characters of the skeletons of our Falconidae, and the 

 work may be completed by a synoptical table of characters. In 

 reproducing my Osteology of Circus, there will be but few, if any, 

 changes made in the original memoir, and the only disadvantage this 

 may occasion will be, perhaps, a repetition of statements in a few 

 instances, if this may be considered a disadvantage. I have a num- 

 ber of skeletons of this harrier whose osteology we will now pro- 

 ceed to describe. 



Skull. In dealing with this part of the skeleton of Circus, I will 

 take into consideration only the skull of the adult individual ; mak- 

 ing no attempt to give exact definitions of the boundaries of the 

 several elements of the skull, a thing which is only possible in im- 

 mature specimens. 1 



We observe upon lateral view [fig. 19] of the skull of this harrier 

 that the premaxillary is produced downward anteriorly into a sharp 

 pointed hook. The upper boundary of this, strongly convex, forms 

 a little less than half of the cuknen, commencing as it does at the 

 apex of the osseous beak, and extending back to where the nasal 

 processes of the bone commence. Here the premaxillary presents 



1 This question will be touched upon, further along, in the skull of another hawk, 

 the writer having in his private cabinet a fine series of skeletons of nestlings of 

 Falco sparverius. 



