54 UPPER CRETACEOUS TELEOSTS 
The cutting edge extends around the apex imparting a slight barbed appearance to 
the tooth both pre-apically and post-apically. The teeth are practically straight 
and most of them are inclined slightly anteriorly rather than vertically downwards. 
The teeth are shortest at the anterior end and increase in size posteriorly reaching 
their maximum length about two-thirds of the way back, after which they again 
decrease in size. The palatine contacts the ectopterygoid below the front end of 
the orbit and it appears that one of the rows, the most internal, of the palatine teeth 
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Fic. 22. Deyrcetis triquetey Pictet. Hyopalatine bones and mandible of the left side 
in medial view. 
is continued back on the ectopterygoid. The teeth on the ectopterygoid are, 
however, shorter, stouter and markedly recurved. Each tooth still exhibits the 
apical cutting region both in front of and behind the apex. The ectopterygoid is 
small in comparison to the palatine and inclined at a greater angle to the horizontal. 
Posteriorly the ectopterygoid meets the quadrate and overlies it laterally. The 
endopterygoid attaches to the internal region of the ectopterygoid and is in the form 
of a flat plate lying medially in the roof of the mouth. The posterior region of the 
ectopterygoid is thickened in two places, the thickenings diverging posteriorly. 
The lower thickened region contacts the quadrate, the upper thickened region passes 
postero-dorsally and forms the attachment region for the rear edge of the endo- 
pterygoid. This latter thickening is continued postero-dorsally by a thickened 
crest on the anterior region of the metapterygoid. This bifurcation of the thickened 
edges of the ectopterygoid is clearly visible from the medial aspect. The meta- 
pterygoid is large with an obliquely inclined crest, the remainder of the bone overlying 
the lateral face of the anterior region of the hyomandibular and attaching to the 
dorsal edge of the quadrate. The hyomandibular is upright with an elongated head 
and a shallow lateral crest passing down the rear edge of the bone. The quadrate 
condyle lies below the level of the occipital border of the neurocranium. 
Dermal upper jaw. Due to the fragmentary nature of the specimens it is 
impossible to ascertain to what extent, if any, the maxilla enters the oral border of 
the upper jaw. Both premaxilla and maxilla are elongated and lie against the 
lateral face of the palato-pterygoid. Anteriorly the premaxilla is wrapped around 
