NO. 19 OLIGOCENE EAGLE WETMORE 9 



Phalanges : Length of phalanx of first toe 32.3 ; transverse breadth 

 at base 11.3. at center 6.2 ; length of basal phalanx of third toe 23.7; 

 length of third phalanx of third toe 19.8. 



Remarks. — The general impression obtained from a survey of the 

 skeleton of Palaeoplaimis is that of a bird with relatively small head 

 like that of a golden eagle, moderately dcvelo])ed wings, strong legs, 

 and large feet with unusually long and powerful toes. The relatively 

 weak development of the tail indicates less rapid flight, or possiblv 

 less addiction to soaring, than is seen in our living buteoninc hawks 

 and our eagles, but at the same time the strong feet suggest a prclatory 

 habit, and the grappling of active prey. 



After some consideration of the peculiarities of the metatarsus, 

 furcula, and humerus, and the other features mentioned in the diag- 

 nosis, it is seen that Palacoplaucus does not fall into any of the recog- 

 nized subfamilies of the Accipitridae. It is like the buteonine group 

 in general but differs in the points already indicated. The form of 

 the pygostyle and of the furcula are somewhat like those of Haema- 

 iornis (formerly called Spilornis^) in the Circaetinae, but no close 

 alignment with this group is indicated. It seems necessary to propose 

 that the form here described be recognized as a distinct subfamily to be 

 called Palaeoplancinae, which should be placed between the Buteo- 

 ninae and the Circaetinae. 



The species is named in honor of George F. Sternberg, skilled 

 collector of vertebrate fossils, through whose efforts many valuable 

 specimens have come to the National Museum. 



^ Swann, H. K., A monograph of the birds of prey, pt. 11, April i, 1933, p. 147. 



