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Show aa-i ox T H E T O X G U E ETC. O F T H E AMERICAX VULTURES. [Dec. 1. edge of the upper lamella, which forms the joint, is neatly rounded off instead of projecting irregularly as in Gypagus. These points will be better understood after an inspection of the accompanying drawings (text-figs. 46-48). It will be seen that my reading of the facts differs slightly from that of Mr. Pycraft. Articular perfection appears to m e to have been arrived at both in Cathartes and Sarcorhamphus from a lower stage such as persists in Gypagus. On the ventral surface of the skull a very conspicuous difference defines Cathartes on the one hand from Sarcorhamphus and Gypagus on the other. In the two latter birds the basitemporal region is deeply excavated, and the sides are prolonged into very marked exoccipital processes. In Cathartes, on the contrary, this region of the skull is much flatter and there are no such conspicuous lateral processes. The inner lamina of the palatines is hooked and overhanging posteriorly in Sarcorhamphus and Gypagus; in Cathartes this region of the bone does not overhang posteriorly and is merely triangular in form. Moreover, in Cathartes the anterior half of the palatine has its broad surface in a plane horizontal, in the other genera it is rotated upwards and is at an angle to the horizontal plane. A final point to which I desire to direct attention is illustrated in the accompanying drawings (text-figs. 46-48). These sketches represent the mandibles of the three genera under consideration viewed from behind. The relatively, as well as actually, much greater thickness of the internal angle in Sarcorhamphus and Gypagus will be apparent. The foregoing account does not at all pretend to be a detailed review of the structure of the skull in the American Yultures. I have economised space by simply dealing with those facts which appear to m e to throw light upon the neutral relationships of the gener&Sarcorhamphus, Carthartes, and Gypagus. Other facts which, in m y opinion, do not bear upon this subject have been ignored. The result is, I think, to show that the Condor and the King Yulture are comparatively slight variations of the same type, while Cathartes stands equally apart from both, a conclusion which is quite in accord with current ornithological opinion. I think it is going rather too far, as has been done*, to include both the former Yultures in one genus ; but it is, in m y opinion, manifestly absurd to combine Cathartes and Gypagus, and to write of Cathartes papa, as has also been done f. * ' Standard Natural History,' Boston, 1885, p. 268. f Taschenberg, ' Bibliotheca'Zoologiea,' v. 1899, p. 3966. |