614 SHUFELDT—OSTEOLOGY OF THE WOODPECKERS.  [0ct.5, 
will be made to stand here for the group in this matter. An adult 
specimen of this form has a humerus measuring 5.4 cms. in length, 
an ulna of 6.5 cms., radius of 5.8 cms., and a total length of the 
skeleton of manus 5.1 cms.—a very well-proportioned limb. 
Owing to its large pneumatic cavity, the humerus is very light, 
while, on the other hand, its shaft is large round. It exhibits the 
usual sigmoid curve, and the extremities of the bone are consid- 
erably expanded. The radial crest is long and rather prominent, 
and the ulnar tuberosity well over-arches the pneumatic fossa. At 
the base of the fossa the air-holes are very fine, and form a diffuse 
group of apertures leading into the humeral shaft. Between the 
ulnar tuberosity and the head of the bone a deep, oblique groove 
exists. 
At the distal extremity the radial and oblique tubercles occupy 
their most usual positions, there being quite a prominent tuber- 
osity on the radial border of the shaft immediately above the latter, 
and a still more conspicuous process produced distally below the 
former from the ulnar border of the bone. 
The radius is nearly straight and slender; its shaft is quite 
uniform in calibre throughout. Its extremities exhibit the usual 
ornithic characters. : 
Fic. 11. Left ulna of Colaptes mexicanus, natural size, drawn by the author 
from a specimen in his own collection. g directs attention to the elevated 
osseous papillz on the shaft for the insertion of the ends of the quills of the 
secondary feathers. 
Nothing especial characterizes the ulna of the Pileated Wood- 
pecker beyond the remarkable row of elevated papillae down the 
