BULLETIN OF THE LABORATORIES 
united and form a quadrate bone making an angle of 25 0 with the cul- 
men or upper line of the beak, their combined width is .45, and they 
form the posterior borders of the nares, being united laterally with the 
maxillaries, anteriorally with the intermaxillary, below with the lachry- 
mals, and posteriorly with the frontals. The distance from the angle 
of the mandible to the top of the nasals is .40. Occupying the top 
of the skull, and apparently restricted to the space between the orbits, 
are the concave frontals. The distance between the orbits is about 
.35. The remainder of the roof of the skull is formed by the con- 
fluent parietals which occupy a larger area than usual on the top and 
back of the skull. From above can be seen a small prominence be- 
hind, which covers the cerebellum, and hence is called the cerebellar 
-prominence. The sides of the triangle are continued backward from 
the ends of the maxillaries by a slender rod consisting of the qnadra- 
tojugal and the jugal which can be studied to advantage when the skull 
is viewed from the side. In this position the skull is seen to present 
the outline of two triangles, the smaller of which, forming the beak, is 
set at an angle of 45 0 with the other. The cutting edges of the jaw 
( tomia ), supported chiefly by the maxillary bones, are slightly curved. 
The tomia are .80 long. The slender rod passing backward and 
downward and forming the lower outline of the second triangle is, in 
the young, composed of two bones, the jugal and quadratojugal. 
Their combined length is .54, the posterior articulation being upon the 
outermost process of the peculiar quadrate bone. This bone is con- 
sidered the homologue of the little ear bone of mammals, known as 
the malleus, but in birds has a very important function — that of giving 
the necessary movability and yet stability to the beak. It is the point 
of attachment of the two important supports of the facial part of the 
skull. The form of the quadrate is very irregular, consisting of a 
body and six processes. The styloid process is the largest and is that 
which connects the bone with the base of the skull ; it is a flattened 
vertical pillar with a large articular surface; jutting out anteriorly is the 
orbital process, about .30 long, which extends into the orbit. Just 
below the orbital is the pterygoid process of rather small size. The 
mandiblar end bears two curved processes so situated that the glenoid 
surfaces oppose the rami from within and behind, while the jaw is com- 
pletely locked by the large articular process of the mandible. A more 
complete articulation could scarcely be conceived. The malar pro- 
cess extends out horizontally and offers an oblique surface to the head 
OF DENISON UNIVERSITY. 
9 
of the quadrato-jugal. The lachrymal bone is very large and hoe- 
shaped, occupying the whole anterior aspect of the orbit. A very 
slender curved process extends backward from its lower angle. The 
lachrymo-nasal space between this and the maxillary permits the free 
movement of the beak on the skull. The lachrymo-nasal foramen is 
quadrate. The optic foramen occupies its usual position on the mar- 
gin of the ali-sphenoid, which is inseparably united with the septum 
intraorbitale and this with the ethmoid still farther forward. There 
is a large irregular foramen above the optic. The greater part of the 
side of the skull behind the orbit is formed by the squamosal , which is 
strongly ridged and forms, first, a strong flange-like process behind the 
orbit and, second, a very long process projecting forward toward the 
corresponding process of the lachrymal. The orbito-sphenoid was not 
detected as a distinct bone, but irregular processes on the ali-sphenoid 
may represent it. The sclerotals are membranous bones, which unite 
to form a ring about the globe of the eye. As seen from below, sev- 
eral new bones appear. At the back of the skull is the large foramen 
magnum, subcordate and quadrate in form and about . 20 in width. 
Above, it is bounded by the supraoccipital, laterally by the exoccipitals, 
and below by the basioccipital. These bones are intimately united 
and the sutures quite obliterated. There is an impressed line on 
either side the foramen. The single occipital condyle is a small knob- 
like process. The basioccipital is quadrate and near its lateral mar- 
gins are the foramina of the carotid and the seventh, ninth, tenth and 
eleventh nerves. The squamosal expands into a large shield-like cov- 
ering over the auditory meatus. J ust inside of the quadrate bone can 
be seen a bony sheath which indicates the former point of union of the 
Meckel’s cartilage. Within the meatus the minute auditory ossicles 
can be seen with a glass. The sphenoid is a pyramidal bone, soon be- 
coming a vertical plate fusing with the ethmoid and inter-orbital sep- 
tum. Here also the obliteration of sutures is complete. The vomer 
is present but inconspicuous. The maxillaries form the sides of the 
beak and, in connection with the premaxillary, form a continuous bony 
ceiling to the roof of the mouth, which is covered with a thick horny 
sheath, so thickened on the edges as to make the knife-like cutting 
tomia. The palatals are movably articulated to the edges of the max- 
illaries by broad bases so that they nearly meet on the median line and 
reach nearly to the jugal, externally. Posteriorly, the palatals extend 
into forked processes, making the whole length .40 of an inch. From 
