Osteology of Circus hudsonius, 15 
the pleural space. A circular pneumatic foramen is found behind 
the transverse process on either side from the thirteenth to the 
Fic. 7. Right lateral view of a part of the axial skeleton of the C’rcus hudsontus. Show- 
ing the shoulder girdle, dorsal division of the vertebral column, the sternum, pelvis, 
caudal vertebra, and pygostyle. The parts are all 7” situ. ‘This figure shows well the 
osterior and detached portion of the pubic element of the pelvis. Same specimen as 
fused in1tto4-. Ribs of left side allremoved. Life size from nature, 
