SHUFELDT. ] OSTEOLOGY OF THE TETRAONIDA. 675 
this fowl the lacrymals are found to be freely articulated to the outer 
borders of the nasals, the frontals barely making any encroachment upon 
them, but in a very old bird we find the lacrymals actually wedged in 
between the frontals and nasals on either side, and the superior peri- 
phery of each orbit formed by the continuous outer margins of a frontal 
and a lacrymal. The prominent bony crest seen in the median line of 
the skull of the Guinea Hen is formed entirely by an uprising of the 
frontals and increases as this fowl becomes older. 
In the Wild Turkey, the external nasal apertures are large and ellip- 
tical, and the various sutures among the bones of the superior mandi- 
ble, long remain clear and distinct as we found it to be the case in the 
Grouse. On a lateral view of the skull we find the arrangement of 
the sphenotic process the same as in all of the Tetraonide ; it differs in 
Numida by being single and very stout; there seems to be no rule gov- 
erning the condition of the orbital septum, for in skulls of Wild Turkeys 
of apparently the same age—in one, large deficiencies will be found in 
this plate while in the other the partition will be entire and quite thick. 
The pterygoids are large and stumpy bones, articulated in precisely 
the same manner as we described them for the Grouse. The vomeris 
short and the spinal chamber in the dry skull capacious and undivided 
by an osseous septum narium. 
The lower jaw is stout and may or may not have the fenestra present 
in its side; behind it has thesharp, upturned processes so character- 
istic of Gallinaceous birds. The ramal apertures is absent in all of 
my specimens of Pavo and Numida, otherwise the birds have inferior 
maxille typical of the family to which they belong. 
We have examined skulls of all of the forms of Lagopus occurring 
in America, and discover but trifling differences existing; in a speci- 
men of L. albus the orbital septum is complete and the cranium of the 
bird is broad across the fronto-maxillary region; a deep median pit ex- 
ists in this region among many of the Quails, less marked in Ortyx, but 
very decided in Cyrtonyx massena, still more in Orortyx picta, the beau- 
tiful plumed Partridge of the Pacific States. In this latter bird we 
find a deep and longitudinal cleft occurring in the median line on the 
superior aspect of the skull, between the orbital margins, that is char- 
acteristic and not found among the other American Quails. 
The skull of the young of Pediecetes, a few days after it has left the 
nest, differs in no great degree from the skull of the young of Centrocer- 
cus—i. €., in points of ossification and the relation of the bones. 
Of the Vertebral Column.—In discussing the development and peculiar- 
ities of the vertebral column, we will still continue to adhere to Centro- 
cercus as our model, explicitly stating names of other species when oc- 
casion requires a departure therefrom. 
In examining the atlas and axis as they occur together in the chick a 
few days old, we find that the neurapophyses of the first have as yet 
failed to fairly meet above in the median line; though they may in 
some instances, as they undoubtedly do, soon touch each other. No os- 
sific centre exists for an atlantal neural spine, as that process is not found 
upon this bone in any of the Tetraonidw. Below the arch the interest- 
ing procedure is progressing in the appropriation of the centrum of this 
segment by the axis. The inferior extremeties of the atlantal neura- 
pophyses have inserted between them a circular ossicle whose plane is in 
the horizontal plane and on a level with the floor of the neural canal of 
the axis. This bonelet eventually becomes the ‘‘odontoid process” of the 
second vertebra. At this stage it is a little less than a millimeter in 
diameter, and in the adult occupying the same position remains a sub- 
