316 MR. AV. P. PYCRAFT ON THE [Apr. 15, 



This brings us to the Ynltiirinre. By most, this sub-family is 

 regarded as of more importance than is allowed in the present 

 scheme : Gadow and Sharpe, for example, according it the 

 rank of a family. That the Vultures have undergone a con- 

 siderable amount of specialization there can be no doubt ; but 

 it seems equally certain that they are not far removed from the 

 Circactince. Suschkin recognizes evidence of two distinct branches 

 in this family — Gypohierax standing at the base of one, and leading 

 to Neophron and Gyps ; Gypaetus at the base of the other, and 

 leading to Yidtiir and Otogyps. 



The Oircaetinag include Circaetus,Geranos2nzias,Helotars%is, and 

 Spilornis. Closely allied, and intermediate between it and the 

 next sub-family — the Circinfe — comes the highly specialized 

 Polyborinse. It seems to me that this sub- family might perhaps 

 as well be included in the Circinee, with which, as Di-. Suschkin 

 shows, it has many characters in common, and in this I can 

 confirm him. 



The Circinae embrace Circus, Geranospizias, Urotriorchis, and 

 Strigiceps. 



The Urubitinginfe I have added on my own responsibility. 

 Dr. Suschkin speaks of them as isolated forms related to the 

 Circaetinm. 



The Buteoninse include Buteo, Archibuteo, T achy trior chis, 

 Geranoaeius, Hupornis, Leucopternis, and apparently Busarellus, 

 Butastur, Anterior, and Astitrimda. 



In the Accipitrinse Dr. Suschkin includes Accipiter, Astur, 

 Melierax, Urospizias, Lophospizias, Scelospizias, and JSfisoides. 



Though we cannot regard this scheme as final, yet, it must be 

 admitted, it is one which is in many respects an advance upon 

 previous arrangements of this most difficult of groups. In its 

 constrxiction an attempt has been made to follow the lines of 

 phylogenetic descent, the only satisfactory basis of classification, 

 yet a peculiarly difficult one in all questions of avian descent, 

 owing to the lack of annectant fossil forms. 



Finally, it is to be noted, the Falconiformes are by no means 

 so uniformly desmognathous as is generally supposed. Mr. 

 Beddard has given several exceptional cases, and in the present 

 paper the list is further extended. But it seems clear that both 

 desmognathous and schizognathous palates are to be regarded as 

 modifications of a Gruine-schizognathous type. The Oathartte 

 have transformed the peculiarities of this type into the unique 

 desmognathism already described. The forms which still retain 

 a schizognathous palate have slightly modified the peculiarities of 

 the original form by loss of the septo-maxillary spurs. Further 

 specialization has resulted in the reduction of the maxillo-palatines 

 to the vanishing point, e. g. Elanus. But the majority of the 

 Falconiformes have greatly increased the size of the maxillo- 

 palatines till they meet in the middle line {a) embracing the nasal 

 septum between them (indirect desmognathism), or (h) meet 

 beneath the septum fusing with one another (complete desmo- 



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