130 UPPER CRETACEOUS TELEOSTS 
The parietals are narrow, transversely orientated strips of bone, at the hind end 
of the frontals. Each parietal bears a small transversely arranged parietal crest, 
but the remainder of the surface is smooth. 
The mesethmoid is short, broad and poorly ossified, but internally thin mem- 
branous sheets of bone extend back to the lateral ethmoids. Laterally the meseth- 
moid is attached to the vomer. 
The lateral ethmoids are flimsy bones representing merely superficial ossifications 
of cartilaginous components. The lateral and ventral regions of the lateral ethmoid 
are however more strongly ossified than the remainder. Ventrally the lateral 
ethmoids are attached to the postero-dorsal region of the palatine. 
A small supraorbital bone lies along the lateral edge of the frontal above the lateral 
ethmoid. The supraorbital is oval and finely ornamented with small tubercles. 
The vomer, which attaches to the undersurface of the mesethmoid, is a small 
shallow bone with a short posterior process. This posterior process extends back- 
wards below the anterior end of the parasphenoid. The vomer is expanded laterally 
and between the mesethmoid and vomer the head of the maxilla articulates. 
The parasphenoid extends for practically the entire length of the neurocranium. 
Below the orbit it widens considerably and consists of a pair of large ventro-laterally 
inclined flanges associated with the endopterygoids. The ascending processes of 
the parasphenoid curve upwards at the posterior end of the orbit to meet the 
prootics in the walls of the myodome. The anterior edge of each ascending process 
is thickened. The course of the efferent pseudobranchial artery is represented by 
a notch in the antero-ventral edge of the ascending process. The foramen for the 
internal carotid artery lies just behind the efferent pseudobranchial notch. Poster- 
iorly the parasphenoid joins the basioccipital. The parasphenoid terminates just 
in front of the hind end of the basioccipital and forms the complete floor of the 
myodome. 
yf epa 
par 10mm f 
Fic. 58. Halec eupterygius (Dixon). Neurocranium in lateral view. 
