312 MR. W. p. PYCIRAFT ON THE [Apr. 15, 



being much reduced and widely separated, but, nevei-theless, 

 bridging the palate ; and this by means of a pair of strap-shaped 

 processes, arising fi-om their inner dorsal boiders, and extending 

 mesially to meet a horizontally expanded plate developed by the 

 infeiior border of the ossified hinder end of the nasal septum. 

 These processes — the anterior septo-maxillary spurs of Pai-ker — 

 feebly developed in Rhinochcetus and Tetrapteryx, are well seen in 

 Psophia (PI. XXXIII. fig. 8) ; and Mr. Beddard was, I believe, 

 the first to point out their homologies and the part they play in 

 the formation of the peculiar palate of the Cathartse. Thus, in 

 describing the palate of Psophia he says, " If these processes were 

 to be increased in size and to meet a bony internasal septum, we 

 should have the 'desmognathous' skull of the American Vultures." 

 It is possible, that at the time Mr. Beddard did not quite grasp 

 how nearly the Psophiine skull appi-oached the realization of the 

 modifications peculiar to the Cathartse, since I gather — fi-om his 

 silence on the point — that thei'e was no trace of an ossified nasal 

 septum in the skull or skulls which he examined. In all the 

 skeletons at the Natural History Musexim, save one, there is no 

 septum, which has apparently been lost in maceration. In this 

 one, it takes the form of a gi-eatly fenesti'ated plate tapering 

 forwards to a point, and terminating at the distal fourth of the 

 external nares. The fenestration in this species is so extensive 

 that only the hinder end and dorsal border are left, but the hinder 

 end dips downwards so as nearly to touch the maxillo-palatine 

 processes. If this septum developed a horizontal plate, as in 

 the Cathartse, we should have the same type of desmognathism 

 which is now peculiar to the last-named group. 



The nasal septum of the Cathartae is more reduced anterioi-ly 

 than in Psophia, never extending foi-wards beyond the posterior 

 third of the external narial aperture (in the skeleton), and in some 

 genera is not even visible on a side view of the skull. In 

 Pseudogryphus and CatharisUs it may be studied to best advan- 

 tage. In the former it extends nearly as far as the middle of the 

 narial apertiu-e, and is fenestrated much as in Psophia. The bony 

 tissue which in Pseudogryphus forms the anterioi- border of the 

 fenestra is wanting in Catharistes, so that the septum is invisible 

 when the skull is seen from the side, but, when viewed from 

 below, the sutures between the horizontal plate of the nasal 

 septum and the septo-maxillary spurs are plainly visible. 



Mr. Beddard, in pointing out the nature of the Cathartine 

 palate, and the probable soui-ce from which it was derived, has 

 given us the key to a veiy important problem — the origin of 

 the Falconiform stem. The Cathartse are the least specialized 

 members of the group, and, it is interesting to note, are also New 

 World forms like Psophia. But the low genei-alized position of 

 the Cathartse is shown as well by other portions of the skeleton as 

 by the skull. We may, I think, safely regard the Cathartfe as 

 the most pi-imitive of the Falconiformes. 



The impoi-tance of a coiiect understanding of the evolution of 



