ESPECIALLY MYCTOPHOIDS 25 
postero-dorsally. A large foramen in the lateral wall of the exoccipital transmitted 
the vagusnerve. Anterior to the vagus foramen is a further smaller foramen for the 
glossopharyngeal nerve. 
The pterotic makes up the posterior two-thirds of the hyomandibular facet and 
contacts the prootic and sphenotic anteriorly within the hyomandibular facet. 
Below the facet, the pterotic contacts the prootic, exoccipital and intercalar. 
The intercalar is small and superficial, lying ventral to the posterior opening of the 
post-temporal fossa. The ventral surface of the intercalar is flattened, but dorsally 
provides a concave facet for the articulation of the ventral limb of the post-temporal. 
The sphenotic is large and forms the postero-dorsal corner of the orbit. Within 
the orbit the sphenotic meets the prootic ventrally and the pleurosphenoid medially. 
The basisphenoid is Y-shaped with a long pedicel which presumably contacted the 
parasphenoid ventrally, although not evident in the specimen. The upper arms of 
the Y are spread out and articulate with the medial edges of the prootic above the 
prootic bridge. These dorsal arms separate the hypophysial fenestra ventrally from 
the optic fenestra dorsally. The basisphenoid also articulates dorsally with the medial 
edges of the pleurosphenoids. The basisphenoid pedicel bisects the opening of the 
posterior myodome, and gave insertion to the posterior edge of the presumably 
membranous interorbital septum. 
The pleurosphenoids are separated in the mid-line by the optic fenestra, which is 
closed by the orbitosphenoid antero-dorsally and the basisphenoid postero-ventrally. 
The pleurosphenoids are attached dorsally to the undersurface of the frontals and in 
this region are only superficially ossified. Along the ventral surface of the frontals 
the course of the superficial ophthalmic nerves is indicated by several small foramina 
through which branches of the nerve passed to the organs of the supraorbital sensory 
canal. 
The orbitosphenoid is a large, median, well ossified bone lying anterior to the 
pleurosphenoids. It contacts the undersurfaces of the frontals dorsally and the 
olfactory nerves passed through a median foramen in its anterior edge. 
Infraorbital bones. The infraorbital bones are shown in lateral view in Text- 
figure 11. A low elongated lachrymal lies at the anterior end of the orbit, followed by 
a second shallow infraorbital. The infraorbitals posterior to the orbit are greatly 
expanded (see also Woodward, 1912, pl. 54, fig. 4) extending back lateral to the 
preoperculum. 
Hyopalatine bones. The hyopalatine bones are shown in medial view in Text- 
figure 10. The hyomandibular is short, broad and forwardly inclined ventrally, 
with a single elongated head. The opercular process is prominent and projects 
posteriorly from the upper part of the rear edge of the hyomandibular. On the lateral 
face a large crest, originating near the posterior region of the head, passes ventrally 
along the posterior edge of the bone, where it ends abruptly. The upper anterior 
edge of the preoperculum rests against the rear edge of this crest. Ventrally the 
hyomandibular tapers to a stout rod of bone. Anteriorly the hyomandibular is thin 
and covered laterally by the postero-dorsal part of the metapterygoid. On the 
medial face there is a large antero-dorsal foramen through which the hyoman- 
