1900.] SHUFELDT—OSTEOLOGY OF THE WOODPECKERS. 605 
in mid-series than they are at the ends; the leading dorsal vertebra 
also bears one of these processes, while the neural spines to the 
last-mentioned are lofty and comparatively narrow antero-poste- 
riorly, and a somewhat reduced one is found on the last cervical. 
Epipleural appendages are seen upon all the true dorsal ribs, but 
they are absent from the extremely slender pair of sacral ribs. The 
last pair of cervical ribs are peculiar in being very stout and broad, 
and from this pair backward through the dorsal series they di- 
minish in width. Most curious of all is the great size of the ante- 
rior pair of sternal ribs, and it is not clear to me at the present 
writing why they should be so. There is no canal passing through 
the ultimate chevron bones and the lower part of the pygostyle in 
the skeleton of the tail in Dryobates. Excepting a few minor de- 
partures, the part of the skeleton we have now under consideration 
in the Ivory-billed Woodpecker essentially corresponds with what 
we see in the last-mentioned genus. Campephilus, however, does 
not have its carotid canal completely closed in—the canal is found 
through the chevron bones of the caudal vertebrae—and a very high 
state of pneumaticity exists throughout. Xemopicus likewise agrees, 
as does the Pileated Woodpecker (C. pc/eatus), and in it the chevron 
bones are pierced by a canal which is extended through the enor- 
mous pygostyle of this bird. It, too, has the vertebrarterial canals 
of the atlas and axis entire. 
Picoides arcticus presents us with nothing in its vertebral column 
and ribs in any way at variance with what we have in general found 
among other Woodpeckers above. In it, as usual, the atlas is 
pierced on either side for the vertebrarterial canal, and the carotid 
canal is slighly open in mid-cervical series, but completely closed 
and very small in the last vertebra or two. Nineteen free vertebrae 
are found between skull and pelvis, and six with a large picine 
pygostyle in the skeleton of the tail. 
In aspecimen of JZelanerpes erythrocephalus at my hand Lalso find 
nineteen free vertebre from occiput to pelvis, with six free tail 
vertebre and a pygostyle. Generally speaking, the characters of 
these and the ribs connected with them are much the same as we have 
already described above for representatives of other American picine 
genera, but still there exists a specific shading difference hard to 
define. The vertebrarterial canal or foramen is closed in by bone 
on one side, open on the other in the case of the atlas, and the cup 
of this bone is largely perforated by an odontoidal fenestra. The 
