8 



SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 8/ 



Of the vertebral column the first and a part of the second cervical, 

 parts of three dorsals, the first four caudals. and most of the pygostyle 

 are preserved. Atlas and axis (fig. i8) in size and general form 

 similar to those of the female red-tailed hawk (Buteo jamaicensis) 

 (thus matching the relatively small head) ; dorsals with most of the 

 processes broken away and offering little in the way of characters ; 

 pygostyle (fig. 19) and other caudal vertebrae relatively large, being 

 as large as those of Buteo rnelanoleiicus; form of pygostyle more like 

 that of Aqiiila chrysactos ; muscular attachments on all caudals slightly 

 less developed than in the modern si)ecies with which comparison 

 is made. 



Fig. 17. — Basal pha- 

 lanx of left hallux of 

 Palaeoplancus steni- 

 brrgi, natural size. 



Fig. 18. — Anterior 

 view of joined atlas 

 and axis of Palaeo- 

 plancus sternbergi, nat- 

 ural size. The bones 

 are somewhat distorted 

 by crushing. 



Fig. 19. — Distal view 

 of pygostyle of Palaeo- 

 plancus sternbergi, nat- 

 ural size. 



Measurements (in millimeters). — .Skull: Length of premaxilla 

 29.8; length of mandible (approximate) 67.0. 



Atlas : Width 9.0 ; depth 8.3. 



Humerus: Length (approximate) 124.3 : transverse breadth across 

 trochlea (approximate) 21.8. 



Metacarpus: Length (18.9; greatest height at proximal end 17.5; 

 transverse breadth of shaft at center 5.5: vertical diameter at same 

 point 6.2. 



Second digit: Length 27.9; greatest breadth at renter 5.2; greatest 

 depth 10.4. 



Femur: Transverse diameter through head 20.1 ; diameter of head 

 8.3 ; transverse diameter of shaft 9.6. 



Metatarsus: Transverse diameter through trochlea (approximate) 

 18.0; transverse breadth of outer trochlea 3.9 ; (jf middle trochlea 5.3 ; 

 of inner trochlea 7.0 ; least transverse breadth of shaft 9.0. 



