8 
BULLETIN OF THE LABORATORIES 
united and form a quadrate bone making an angle of 25° 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 cerebella}' 
prominence,. The sides of the triangle are continued backward from 
the ends of the maxillaries by a slender rod consisting of the qiiadra- 
tojugal and the jugal which can be studied to advantage when the skull 
is viewed front 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° with the other. The cutting edges of the jaw 
(tofnia), 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 quadratojugah 
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 
l3ody 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 
