604 SHUFELDT—OSTEOLOGY OF THE WOODPECKERS.  [0ct.5, 
solid appearance to the mid-cervical segments from a posterior 
view. A hypopophysial canal is well marked, and this in the 
tenth, eleventh and twelfth vertebrze is replaced by very large and 
strong processes. 
Among these segments the usual form of articulation that we find 
in the highest groups of birds prevails both anteriorly and pos- 
teriorly. 
In the dorsal division of the spine large neural spines are present 
and the diapophyses are long and broad, developing at their outer 
extremities, above, short spine-like metapophyses. 
Pneumaticity obtains in the case of the thoracic ribs, and these 
bones are rather wide in the antero-posterior direction and com- 
pressed transversely. The epipleural appendages are broad and not 
lengthy, usually in any casé only reaching to the middle of the next 
succeeding rib. They always fuse with the margin of the latter. 
Foramina for the admission of air are likewise to be seen at the 
ends of the true costal ribs. 
Very spreading and somewhat downwardly-inclined transverse 
processes characterize the six free caudal vertebra in Codaftes. 
Their centra are small and the bones are not pneumatic. The 
neural canal is almost capillary in its calibre, while in the two ulti- 
mate segments a codssified, strong chevron bone is seen, which is 
likewise pierced antero-posteriorly in the last one by a foramen. 
This foramen is also carried on through the lower part of the pe- 
culiarly formed pygostyle. The neural spine of the last-mentioned 
is lofty, being thin-edged in front and on top, while posteriorly it 
is thicker. This bone also codssifies with the caudal vertebra next 
in front of it, the transverse processes of which remain undiminished 
in size. Behind, the pygostyle at its lower part flares out as a broad, 
transversely-disposed hexagonal plate of bone, constituting a well- 
known character of the Pez. 
So far as number of vertebrze is concerned and arrangement and 
number of ribs, Dryobates essentially agrees with Co/apies, but in 
the former we find some interesting morphological differences. In 
Dryobates the cup of the atlas is always perforated, and at the sides 
of this bone, either upon one side or the other, the osseous span 
for the vertebrarterial canal may not be quite complete, while on 
the other hand the hypapophysial canal for the carotid artery is 
entirely surrounded by bone, and the union below is firm. The 
last five cervicals support long hypopophyses which are narrower 
