SHUFELDT.] OSTEOLOGY OF THE EREMOPHILA. 629 
have a certain value when we come to compare the various skulls of the 
Class. 
The primary elements of the occipital, or first cranial vertebra, have 
become completely fused together, and with such other bony elements of 
the vertebra beyond, of the mesencephalic arch, with which they usually 
articulate. The well-marked superior curved line that limits muscular 
attachment above would seem to be, and in all probability is, about the 
position of the lambdoid suture, and the superior boundary of the bone 
we are describing. This curved line descends and is gradually lost along 
the boundaries of the mastoids and occipitals on either side. Externally 
and inferiorly we find the occipital pierced by the usual foramina of the 
basi-cranii. The group for the exit of the eighth pair of nerves, being 
the most anterior of all, are situated on either side, in well-marked depres- 
sions or pits, some 7 millimetres apart. Back of these and nearer to- 
gether are the minute precondyloids, looking forwards and outwards for 
the passage of the hypoglossal nerves. These last foramina are just an- 
terior to the border of foramen magnum; this latter aperture is of good 
size, comparatively, having antero-posterior and transverse diameters 
of 3 millimetres each, with an additional millimetre for the oblique 
diameters, making the latter 4 millimetres each. It is subcircular in 
outline, its anterior rim passing around a depression that lies just in 
front of the condyle, giving the latter the appearance of jutting out 
into the foraminal space. The condyle is nearly sessile, having the 
merest trace of a neck, hemispheroidal in form, with an horizontal 
and average diameter of .5 of a millimetre. Above and midway, later- 
ally, the borders of the foramen are encroached upon by the petrosal on 
either side, giving it rather a constricted appearance; from these points, 
as we follow the posterior moiety of the foraminal periphery, we find it 
to be grooved, each groove ending posteriorly within a millimetre of each 
other, in a minute foramen that traverses the internal table of the era- 
nium upwards, outwards, and forwards for a short distance, thence to 
arch around, as a sinus, the epencephalic fossa, to meet in the longitu- 
dinal sinus coming from above. This arrangement obtains in the Cor- 
vide, and some other families, where it is more strongly marked. The 
diapophyses of the occipital vertebra are in a plane but a little lower 
than the basi-sphenoid; they form, as is quite common, the horizontal 
floor of the cavity of the otocrane, and blend with the surrounding bones. 
A moderately well-marked ‘cerebellar prominence” occupies its usual 
site in the middle line; no openings or foramina are ever to be discovered 
either at its summit or laterally, as seen in some other birds (Anatide, 
Strigide). It divides the shallow temporal fossze that slope away from 
it on either side, and varies somewhat in size in different individuals. 
From the upper region of the ear and the superior boundaries of the 
temporal fossze to the iine of that psuedo-articulation, the fronto-man- 
dibular, this bird’s cranium is remarkably smooth, and of a clear white, 
and, owing to the extraordinary amount of dipléic tissue, possessing a 
peculiar translucency. The median furrow is only well marked as it 
passes between the orbits; the superior peripheries of these cavities, as 
constituting one of the boundaries of the surface under consideration, 
are sharp at first, rounding as they include the lacrymals, and entirely 
devoid of any notches or indentations. As is usual, all sutural traces 
are absent (Pl. IV, Fig. 25). The transverse line of the fronto-mandib- 
ular juncture is slightly coneave backwards along its middle third, the 
extremities sloping a little downwards and backwards. The joint mo- 
tion is only moderately free. No well-marked suture defines its exact 
locality, as in Harporhynchus and others. The bones that go to form 
