Page 646. 
112 THE ANATOMY OF THE HUIA BIRD. 
nor with the vomer, which they partly embrace. There is no ossifica- 
tion in the nasal septum anterior to the vomer. 
The whole cranial configuration (Fig. 1) closely resembles that of 
Sturnus ; but the mandible, instead of being bent upwards, is straight. 
Like it, the palatines are narrow and approximate; the antero-internal 
angles of the posterior portions of those bones are reduced and rounded 
off, as is sometimes the case with Stwrnus (Mus. Roy. Col. Surg. No. 
1539, Ost. Coll.). The vomer is completely truncated in front, and 
is not prolonged forwards at its external angles, as in Corvus and its 
allies. - 
The zygoma is not so slender as in Sturnus; but the curves are 
similar. The articular surfaces on the quadrate bone for the mandible 
are proportionally very large. 
The anterior extremities of the pterygoid bones articulate with 
the sphenoidal rostrum much as in Corvus, meeting in the middle line 
behind the posterior extremities of the palatines for a short distance. 
The maxillo-palatines in their approximate portions are shorter 
from before backwards than in Stwrnus, and much resemble those of 
Corvus. 
The antero-inferior processes of the orbit are large and spongy ; 
they almost touch the zygoma. But the most characteristic portion 
of the skull of Heteralocha is the occipital region; and in this it 
presents a great exaggeration of the peculiarities of Stwrnus and its 
allies. 
In Corvus (Fig. 4) and most Passerines the digastric muscles occupy 
a narrow space intervening between the auditory meatus and the mass 
of occipital muscles, not extending so high up the skull as the latter. 
The occipital ridge encloses a space elongated from side to side and of 
but little depth. 
In Sturnus the digastrics are much broader, and they narrow the 
occipital space; they also extend up the skull to so great an extent 
that they nearly meet in the middle line above the origin of the 
biventres cervicis muscles; but in Heteralocha (Fig. 3) they are of 
still greater size, and meeting above the middle line they form a strong 
ridge, which extends for some distance into the parietal region verti- 
cally. This peculiar development of these muscles produces a corre- 
sponding change in the shape of the space enclosed by the occipital 
ridge. In Heteralocha it is almost circular, and it extends some way 
above the foramen magnum. In Stwrnus there is an approximation 
to this condition. 
A vertical parieto-occipital ridge in many other birds closely re- 
sembles that of Heteralocha; but it is the median limit of the temporal 
fossa in most. 
Correlated with this extensive digastric origin is a large surface 
