UNIVERSITY OF CALIFORNIA PUBLICATIONS 



BULLETIN OF THE DEPARTMENT OF 



GEOLOGY 



Vol. 9, No. 9, pp. 105-109, 3 text figures Issued March 10, 1916 



TWO VULTURID RAPTORS FROM THE 

 PLEISTOCENE OP RANCHO LA BREA 



BY 



LOYE HOLMES MILLEE 



\ 



CONTENTS 



PAGE 



Introduction 105 



Description of Species 106 



Neophrontops americanus, n. gen and sp 106 



Neogyps errans, n. gen and sp 108 



INTRODUCTION 



Those decidedly degenerate falconiforms which are classed in the 

 old-world family Vulturidae occupy the same bionomic position within 

 their realm as is filled, in the new world, by the Cathartiformes and 

 the aberrant Polyborinae. An aggressively rapacious habit has, in the 

 vulturids, given place to the more passive manner of the carrion feeder 

 — a change that has its anatomic reflection, to some extent, in the beak 

 but most positively in the foot. This latter member practically ceases 

 its function as offensive armament and loses also in large measure its 

 power as a prehensile organ. The cannon bone of these passive faleoni- 

 forms may then be very properly expected to show interesting modi- 

 fications of the raptorial type. Such is certainly the case. 



The tarsometatarsus of vulturids is characterized by weak contours 

 throughout. The anterior aspect displays but slight excavation in its 

 proximal region. Passing down the shaft and forming the antero- 

 external contour of the bone is a ridge which, in the active raptors, 

 is sharp and high. In vulturids this ridge is much mollified — a con- 



