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Show 316 MR. W. P. PYCRAFT ON THE [Apr. 15, This brings us to the Vulturinse. 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 considerable 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 Vultur and Otogyps. The Circaetinse include Circaetus,Geranospizias,Helotarsus, and Spilornis. Closely allied, and intermediate between it and the next sub-family-the Circinse-comes the highly specialized Polyborinse. It seems to m e that this sub-family might perhaps as well be included in the Circinse, with which, as Dr. Suschkin shows, it has many characters in common, and in this I can confirm him. The Cii'cina^ embrace Circus, Geranospizias, Urotriorchis, and Strigiceps. The Urubitinginae I have added on m y own responsibility. Dr. Suschkin speaks of them as isolated forms related to the Circaeiino3. The Buteoninse include Buteo, Archibuteo, Tachytriorchis, Geranoaetus, Rupornis, Leucopternis, and apparently Busarellus, Butastur, Antenor, and Asturinula. In the Accipitrinae Dr. Suschkin includes Accipiter, Astur, MeXierax, Urospizias, Lophospizias, Scelospizias, and Nisoides. 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 construction 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 cprestions 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 Cathartae 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 betAveen them (indirect desmognathism), or (b) meet beneath the septum fusing with one another (complete desmo- 9 |