Osteology of Circus hudsonius. 35 
anterior free coccygeal vertebra; there are six (6) free coccygeal 
vertebrae and a large pygostyle ; there are nine (9) pairs of ribs in 
all, the first two pair and the last one are without unciform appen- 
dages ; the first two pair are free; the last two pair articulate 
with the anchylosed vertebrae beneath the ilia; seven pairs, inter- 
mediate, articulate with the sternum through hamapophyses. 
15. The pre-acetabular surface of the pelvis is double the extent 
of the post-acetabular ; the ilio-neural canals are sealed over; the 
anterior fourth of the pubis closes in the obturator foramen, the 
hinder three-fourths of this bone is free, attached only to the 
ischium by ligament ; a considerable space exists between the two 
portions. 
14. The coracoidal grooves of the sternum decussate above the 
trihedral manubrium ; the xiphoidal extremity of this bone may 
show one or two foramina in it, on either side, and its border is 
gently convex forwards. 
15. The scapular process of the coracoid does not reach the 
clavicle. (Negative character. ) 
16. The humerus is the only pneumatic bone of the wing ; 
there is a mid-apical summit to its radial crest; the ulna is 11.5 
centimeters long; there is an os prominens present over the car- 
pus ; the digits of manus are devoid of claws, though pollex may 
possess one. 
17. The femur is the only pneumatic bone of the pelvic extrem- 
ity ; the lowest points of its condyles are in the same plane to 
which the axis of the shaft is perpendicular ; the patella is single ; 
the tibia is one centimetre shorter than the ulna, it has the bony 
bridge below to confine the extensor tendons ; the hypotarsus of 
the tarso-metatarsus consists of two separate processes, neither 
are extended down the shaft ; the first metatarsal is a free and 
large bone, and the arrangement of the phalanges of the digits 
of pes is upon the most common plan ; the long axis of the proxi- 
mal phalanx of the inside toe is-less than half as long as the long 
axis of the phalanx that next succeeds it. 
