96 UPPER CRETACEOUS TELEOSTS 
half the length of the neurocranium. The lateral ethmoid, at the anterior end of 
the orbit, is attached to the underside of the frontal, and ventrally is associated with 
a postero-dorsal expansion of the palatine. The frontal tapers anteriorly towards 
the mesethmoid region. 
Jaws and suspensorium. The hyomandibular is large and vertical with part of its 
lateral face covered by the metapterygoid. The quadrate is large and triangular 
with a prominent transverse condyle at its ventral extremity. The ectopterygoid 
is an elongate laminar bone bearing a uniform row of teeth. The teeth are large, 
laterally compressed, just noticeably recurved, regularly spaced and decreasing 
in length towards the posterior end of the bone. The impression of a laminate 
endopterygoid is visible immediately below the orbit. The palatine is large and 
tumid and bears a single, enlarged terminal tooth set at go° to the main body of the 
bone. Posteriorly the palatine is associated with the lateral ethmoid dorsally and 
the ectopterygoid ventrally. The palatine tooth is considerably larger than the 
teeth present on the ectopterygoid but in all other respects closely resembles them. 
The lateral face of the palatine bears traces of an obliquely inclined groove which may 
have housed the head of the maxilla. 
The premaxilla appears large and irregularly triangular in outline. Impressions 
of the oral edge of the bone, between the anterior ectopterygoid tooth and the 
palatine tooth, show clearly that the premaxilla bore a row of small acutely pointed 
teeth. The premaxilla may occupy more than half of the oral border of the upper 
jaw with the maxilla entering the gape behind it. The maxilla is a stout, smooth, 
untoothed strut of bone. 
The mandible is long and deep, its maximum length being almost four times its 
depth, and its minimum depth occurring at the symphysial end. The dentary 
forms the complete upper border of the jaw and well over half of the lateral face and 
the ventral margin. Teeth are present in a regularly spaced row with the anterior 
tooth at the symphysial end being greatly elongated. The jaws are closed in the 
specimens examined and the anterior dentary tooth lies against the anterior face of 
the palatine tooth and protrudes dorsal to it. The rest of the mandibular teeth 
are at most half as long as the anterior tooth and they decrease in size posteriorly. 
The articular bone forms the posterior end of the jaw and bears the articular facet 
for the reception of the condyle. The facet is rolled both anteriorly and posteriorly 
around the condyle and a small retroarticular process is produced posteriorly. 
The preoperculum could not be observed in either of the specimens examined, 
although from the uprightness of the suspensorium it can be assumed that the 
preoperculum was vertical and relatively narrow. The operculum is large and 
considerably deeper than it is long. The facet for the articulation with the hyo- 
mandibular is positioned approximately midway along the straight anterior edge of 
the bone. The posterior edge of the operculum is smoothly rounded throughout. 
A horizontal strengthening ridge passes across the inner face of the bone from the 
articulatory facet to the posterior edge. The lateral face of the operculum is 
ornamented with a few weak ridges radiating from the region of the articulatory 
facet. A suboperculum is present but its limits are difficult to determine. 
