OSTEOLOGY OF BIRDS 9 



The next genus Circus is also represented by but one species in 

 this country, and I have already published an account of its oste- 

 ology in the New York Journal of Comparative Medicine and Sur- 

 gery, for April 1889. It will be incorporated here: 



Circus hudsonius 



There are many skeletons in my private cabinet of this well known 

 harrier. 



Our genera Accipiter and Astur have four species known to orni- 

 thologists, viz : 



Accipiter velox Astur atricapillus 



Accipiter cooperi Astur atricapillus striatulus 



Skeletons of several of them are to be found in my material, and 

 Dr W. S. Strode of Bernadotte, 111., has kindly favored me with 

 others, to be used in the present connection, and for similar favors 

 I am indebted to Mr T. D. A. Cockerell. 



The genus Parabuteo has but the species 



Parabuteo unicinctus harrisi 



This is Harris's hawk, F a 1 co harrisi of Audubon, and I 

 regret to say that I have not examined its skeleton. 



Of our long list of species representing the genus Buteo, some 13 

 species, I have studied only a few representative ones, as Buteo 

 I i n e a t u s , Buteo b o r e a 1 i s c a 1 u r u s ", and parts of 

 skeletons of others. 



Urubitinga has but the one species in our avifauna, the Mexican 

 black hawk, 



Urubitinga anthracina, 



and I have investigated its skeletal structure carefully. 

 Asturina also has but the species 



Asturina plagiata, 



and Mr Herbert Brown of Tucson, Ariz., has kindly supplied me 

 with skeletons of this Mexican goshawk. 



The "Rough-legged hawks " of the genus Archibuteo, have three 

 species, viz : 



Archibuteo lagopus Archibuteo ferrugineus 



Archibuteo lagopus sancti-johannis 



