1900. ] SHUFELDT—OSTEOLOGY OF THE WOODPECKERS. 603 
this group have this feature quite strongly marked in their skele- 
tons. Further consideration of this limb shows the presence of a 
good-sized os humero-scapulare; it shows the papillz along the 
shaft of the ulna for the ends of the quills of the secondary wing- 
feathers ; it shows the presence of a rudimentary sesamoid at the 
elbow; and it shows, even at this early age, the ossicles at the 
wrist number but two free ones, all the others having duly fused 
with the proximal extremity of the metacarpus. Peculiarities of 
the bones composing the hand can best be studied in old birds, 
which we will do further on. 
Upon examining the skeleton of the pelvic extremity in this 
nestling, I find ossification of the several bones composing it so 
far advanced that nothing would be gained by a description of 
them in their present state, and it will be better to study them also 
in a matured individual. Students will comprehend just how rapid 
this ossification has been when I tell them that even at this early 
stage of this Woodpecker’s development the line of sutures between 
the condyles and the lower end of the shaft of tibio-tarsus has 
been absorbed, a condition which likewise obtains in the femur. 
A goodly patella has also ossified. 
Taking up next the skeleton of an old individual of Colaftes 
mexicanus, we find some very good characters in its vertebral col- 
umn, in addition to those described above. With respect to the 
atlas, it is peculiar in having the vertebrarterial canal, upon either 
side, completely enclosed by bone. It also has a very broad neural 
arch, and its cup for the condyle is unperforated in many speci- 
mens. In the axis we find both neural spine and hypopophysial 
process prominently developed, and in this vertebra the vertebrar- 
terial canal is also present and of some length, being enclosed by 
bone. Both atlas and axis are highly pneumatic, as are all the free 
vertebree of cervical and dorsal regions. ‘This not only obtains in 
Colaptes, but in other Picz. Conspicuous neural spines are also seen 
upon the third and fourth vertebrae, with less evident hypopophysial 
ones. In both these last a broad interzygapophysial bar exists 
upon either side, and with regard to the remaining cervical verte- 
bree they are chiefly noted in not possessing parial parapophysial 
spines, those processes so characteristic of the mid-cervical verte- 
bree in the vast majority of the Passeres, Zygapophysial processes 
in these vertebrze are short and thick, which fact lends a peculiar 
PROC, AMER. PHILOS. SOC. xxxIx. 164. NN. PRINTED DEC. 6, 1900. 
