ESPECIALLY MYCTOPHOIDS 131 
The occipital condyle is circular and concave and formed of both basioccipital and 
exoccipitals. The basioccipital contacts the exoccipitals dorsally and the prootics 
antero-dorsally. Internally the basioccipital forms the walls of the posterior parts 
of the otolith chambers and the roof to the posterior myodome. The otolith 
chambers extend anteriorly to terminate in a recess within the prootic, lateral to the 
prootic bridge. 
The prootic extends medially to meet its partner forming the prootic bridge above 
the myodome. Dorso-laterally the prootic contacts the sphenotic within the 
anterior cup-shaped part of the hyomandibular facet. The orbital face of the 
prootic, above the prootic bridge, meets the sphenotic dorso-laterally, the frontal 
dorsally and the pleurosphenoid dorso-medially. The pars ganglionaris is a shallow 
medial recess in the prootic, lateral to the prootic bridge. The pars jugularis is a 
short horizontal canal lateral to the pars ganglionaris. Two foramina pass from the 
pars ganglionaris into the pars jugularis. The anterior foramen is the trigeminal 
foramen, the more posterior the facial foramen. The hyomandibular nerve passed 
through the facial foramen into the pars jugularis and out through the posterior 
opening of the pars jugularis. The anterior opening of the pars jugularis is 
separated from the posterior opening by a narrow splint of bone. The posterior 
opening transmitted the hyomandibular nerve, the jugular vein, and the orbital 
artery. The palatine nerve did not enter the pars jugularis but passed through a 
small foramen medial to the facial foramen down into the myodome. The anterior 
opening of the pars jugularis is a vertically elongated slit-like aperture through which 
passed the jugular vein, the orbital artery, and the remainder of the trigeminal and 
facial nerves. 
The exoccipitals meet above and below the foramen magnum and each contributes 
to the occipital condyle. Laterally the exoccipital has a prominent foramen which 
transmitted the vagus nerve, the opening being slightly overhung by a flange of 
bone. The glossopharyngeal foramen is smaller and just anterior to the vagus 
foramen. Both of these foramina lie within a groove extending from the posterior 
part of the exoccipital to the posterior opening of the pars jugularis on the prootic. 
Lateral to the occipital condyle and immediately below the vagus foramen, two or 
three very small foramina transmitted the occipital nerves. Laterally the exocci- 
pital is deeply excavated into a membranous concave depression which housed 
pharyngeal musculature. On the posterior face of the skull the exoccipital meets 
the supraoccipital dorso-medially and the epiotic dorsally and dorso-laterally. 
The pterotic bears a dorsal crest forming the outer wall of the post-temporal fossa. 
On the lateral face of the neurocranium the pterotic joins the sphenotic and prootic 
in the hyomandibular facet. The more posterior part of the hyomandibular facet 
is made up of the pterotic alone. The otic branch of the infraorbital sensory canal 
passed within the pterotic crest opening anteriorly above the sphenotic. The 
pterotic crest also delimits the dilatator fossa which is an excavation of the dorso- 
lateral surfaces of both the sphenotic and pterotic. 
The intercalar is a small bone, superficial in position, covering part of the suture 
between the exoccipital and pterotic. The intercalar is wrapped around the 
