31 
process, contributing to the formation of the postorbital bar, is particularly 
long and slender and passes up on the inner side of, and in a long contact 
with, the short descending process of the postfrontal and the front border 
of the inner wall of the postfrontal pocket. Posteriorly the jugal exten- 
sively covers the quadrato-jugal and abuts against the outer front border 
of the quadrate for some distance above the quadrato-jugal. 
Quadrato-jugal. (Qj.). Figures 3, 4, 15. This bone is a thin 
subtriangular plate, slightly higher than long, highest anteriorly and 
longest near the base. Its front border is straight, the lower one nearly 
so but undulating, and the posterior one curved forward above. It thins 
to the front border which is approximately vertical when the bone is in 
position. More than one-half of the external surface is covered by the 
jugal in a close, rather smooth contact lacking the numerous inequalities 
of the junction of the jugal with the maxillary. Posteriorly the quadrato- 
jugal narrowly overlaps the quadrate whose antero-external border is 
emarginated to receive it. A groove is developed in the border behind 
the apex into which the front border of the quadrate above its emargination 
fits. 
Quadrate. (Q.). Figures 3, 4, 16. This bone consists of a 
transversely compressed bar from whose inner surface a large, thin flange 
is directed inward and forward. It connects with the quadrato-jugal and 
jugal antero-externally, with the pterygoid internally by means of the 
flange, with the squamosal superiorly, and with the surangular and articular 
interiorly. It occupies an almost vertical position in the skull with the 
head immovably fitted into the pit in the squamosal, and with the lower 
end in the mandibular cotylus. 
Viewed from without it is narrowest above, and bent slightly forward 
from either end so as to have an evenly concave posterior outline. Below 
the midlength the anterior border is broadly but shallowly emarginated 
for the reception of the narrowly overlapping posterior curve of the quad- 
rato-jugal. The anterior border starting from the head, with the latter’s 
transverse thickness, becomes thin in its descent to the quadrato-jugal 
overlap where it thickens to some extent, but is again thin for a short 
distance above the lower end of the bone. In its upper part the quadrate 
presents a flattened surface facing outward but with a slight obliquity 
inward and backward, and the posterior border is obtusely angulated. 
Approaching midlength the external surface, with an increasing obliquity, 
twists inward so as to form a face directed nearly backward and ends 
inwardly in a narrow border which is the downward continuation of the 
upper posterior angulation. At the lower end the posterior surface is 
again angulated. 
The inwardly and forwardly directed flange of the quadrate is given 
off from the inner surface of the main portion. Its base extends the whole 
length of the bone and is situated, in the lower half, about midway between 
the front and back borders, but toward the top it passes nearer to the 
back border. The flange is thin, triangular in lateral outline, and reaches 
its greatest protrusion in line with the centre of the quadrato-jugal contact 
8329 - 3 ^ 
