28 UPPER CRETACEOUS TELEOSTS 
borne teeth. Anteriorly the maxilla lies medial to the premaxilla where it is as- 
sociated with the palatine. Posteriorly the maxilla enters the gape behind the pre- 
maxilla. In his original description Woodward (1901 : 260) identified the palatine 
as the premaxilla and the ectopterygoid as the maxilla. Later Woodward (1912 : 
246), using the specimen considered here, identified the bones correctly. 
Mandible. The mandible is shown in medial view in Text-figure 10, and lateral 
view in Text-figure 11. It is long and not particularly deepened. The dentary 
forms the whole of the oral border of the bone and almost all the ventral border. 
The posterior edge of the dentary is deeply indented and has a tube opening at the 
posterior end which is continued as a groove on the face of the articular. This tube 
and groove housed the mandibular sensory canal. The oral edge of the dentary 
is thicker and stouter than the remainder of the bone and bears teeth. The teeth 
are in a single row, of unequal size, and irregular distribution. There are approxi- 
mately 7 acutely pointed, recurved teeth. The teeth are laterally compressed 
and arranged at a slightly oblique angle to the long axis of the mandible. The three 
anterior teeth are the largest and occur a short way back from the symphysial 
region. These three large teeth appear to occupy the gap between the two palatine 
teeth when the jaws are shut. Behind these large teeth, three or four small teeth 
occur and posterior to these, one or two somewhat larger teeth. The outer face of 
the dentary is unornamented although several longitudinal ridges are present above 
the mandibular sensory canal. 
The articular facet for the reception of the condyle is concave and transversely 
orientated. The facet is divided mesially by a ridge of bone corresponding to the 
mesial constriction of the condyle. The articular has a slight retroarticular process 
which is laterally grooved for the reception of the mandibular sensory canal. 
The angular is a small slip of bone applied to the postero-ventral surface of the 
articular below the retroarticular process. 
Opercular bones. The opercular bones are shown in medial and lateral views in 
Text-figures Io and 11. The operculum is large and deep with a concave anterior 
edge. Posteriorly it is rounded but the ventral edge is obliquely inclined. The 
outer face of the operculum is smooth and unornamented. The opercular facet is 
large and in the uppermost region. The facet extends medially and is supported by 
a strengthening ridge which passes back horizontally across the internal face of the 
operculum. 
The suboperculum is prominent and lies internal to the ventral edge of the oper- 
culum. The posterior and ventral edges of the suboperculum are thin and 
rounded. 
The interoperculum is roughly oval in shape with thickened anterior and ventral 
edges. The interoperculum lies medial to the ventral preopercular region. 
The preoperculum is narrow and inclines forwards ventrally. Its anterior edge 
rests against the posterior face of the hyomandibular crest and the posterior edge of 
the quadrate. The anterior region of the preoperculum is thickened and contains a 
deep groove overhung by a flange for the preopercular sensory canal. 
