1903.] AND >YINDPIPE OF THE AMERICAX VULTURES. 389 



Interrelationships of the Genera Cathartes, Sarcorhamphus, 

 and Gypagus. 



The foregoing remarks upon the windpipe lead to the con- 

 sideration of the relationships inter se of the American Vultures. 

 Garrod pointed out * the agreement of Sarcorhamphus and 

 Gypagus in possessing the femoro-caudal, which is absent in 

 Cathartes. Py craft, in an osteological survey of the " Falconi- 

 formes"t, has noted characters, some of which lead him to bracket 

 together Gypagus and Sarcorhamphus, though others do not 

 apparently justify such a juxtaposition. On the whole, it seems 

 to me to be clear that the skulls of Sarcorhamphus and Gypagus 

 are more like each other than either is to the skull of Cathartes ; 

 and I shall attempt to justify this view by calling attention to a 

 few minutife which have not been dwelt upon in this connection. 



The outline of the skull, as seen from the side, is very charac- 

 teristic. Cathartes has, relatively speaking, a long low skull with 

 a proportionately longer maxillary and premaxillary region ; it is 

 almost Cormorant-like in aspect. In the other two geneiu this 

 i-egion is deeper and shorter and descends with more of a curve, 

 instead of possessing an upper contour-line which is almost a 

 straight line. The premaxillary region, in fact the end of the 

 beak region, is much more inflated in Gypagus and Sarcorhamphus 

 than in Cathartes. The pervious nostrils are of greater length and 

 narrower across in Cathartes than in the two other genera which 

 agree with each other in this featui'e ; moreover, in Gypagus 

 and Sarcorhamphus the conjoined maxillary plates are visible as 

 projecting forward beyond the posterior end of the nostril, more 

 especially in Gypagus. In Cathartes they are not so visible. On 

 the lateral aspect of the skull another curious though small differ- 

 ence may be noted, which serves to ally Sarcorhamphus and Gypagus 

 and to divide them both from Cathartes. In the last-mentioned 

 bird Mr. Pycraft ha,s correctly figured % a groove which he terms 

 the " nasal hinge." This appears to separate off the lacrymal (fused 

 to the frontal) fi'om the nasal in front. The suture in question is 

 semicircular and with the convexity anterior. In both Sarco- 

 rhamphus and Gypagus the hinge is present but has more the form 

 of a half ellipse ; moreover, the concavity is forward and it thus 

 appears as if a backward process of the nasal were embraced by 

 the concave anterior margin of the laciymal. Mr. Pycraft has 

 also figured §, behind the nasal hinge in the same bird, a strong 

 ridge which presumably marks the boundary of the lacrymal, and 

 is prolonged so as to slightly overhang the orbit. This ridge is; 

 quite absent in both Sarcorhamphus and Gypagus, the orbital 

 margin of which is here smooth. It must be admitted, however-,, 

 that, in one point exhibited in this particular region of the skull,. 

 Cathartes is rather intermediate between the Condor at one extreme 

 and Gypagus at the other. This is the backward direction of the- 



* Collected Papers, London. 1881, p. 210. 



t P. Z. S. 1902, vol. i. p. 277. 



X Loc. eit. pi. xxxii. fig. 1, nJi. 



§ Fig. 10. Wrongly ascribed in the e.vplanatioii of plates to Scrpciilarius.. 



