ESPECIALLY MYCTOPHOIDS 183 
The quadrate is a large, triangular bone with a prominent transversely arranged 
condyle. The posterior edge of the quadrate is thickened and deflected laterally 
and bears a vertical groove posteriorly. The postero-dorsal edge of the quadrate is 
slightly excavated, indicating the upper limit of the symplectic groove on its medial 
face. The symplectic is a vertical rod-like bone, internal to the quadrate. The 
anterior end of the quadrate lies against the lateral surface of the posterior end of the 
ectopterygoid. 
The ectopterygoid is a long narrow strut of bone slightly thickened posteriorly. 
The ventral edge of the ectopterygoid is flattened and bears teeth. Anteriorly the 
bone has some three rows of slender, acutely pointed recurved teeth, but more 
posteriorly the tooth row number decreases. The ectopterygoid contacts the 
palatine anteriorly and is quite firmly attached to it. The endopterygoid is plate- 
like and attached to the internal edge of the ectopterygoid. The metapterygoid is a 
very large thin sheet of bone covering most of the lateral face of the hyomandibular, 
contacting the quadrate and ectopterygoid ventrally and the endopterygoid 
anteriorly. 
The palatine is elongate, stout and forms a direct continuation of the ectopterygoid 
anteriorly. Postero-dorsally it is attached to the ventral region of the lateral 
ethmoid, and anterior to this has a small dorso-laterally inclined maxillary process. 
The palatines are very close together at the anterior end of the snout. Ventrally the 
palatine is flattened and covered irregularly by teeth. The teeth are slender, 
acutely pointed and strongly recurved. 
Dermal upper jaw. The dermal upper jaw is shown in lateral view in Text-figure 
84. The premaxilla is prominent, thin and elongate. Anteriorly it appears to 
contact its partner in the mid-line just in advance of the mesethmoid. The outer 
face of the premaxilla is smooth and curved. It is of relatively uniform depth along 
most of its length but tapers somewhat posteriorly. 
The maxilla is long and slender, forming almost exactly half of the gape. The 
head of the maxilla is inflected and bears a medial excavation which houses the 
maxillary process of the palatine. The anterior region of the maxillary head is 
drawn out in front of this medial excavation and would appear to lie on the dorsal 
surface of the wing-like mesethmoid extension. 
Teeth are present on both of the bones in the dermal upper jaw. The maxilla 
bears a double row of small acutely pointed teeth on that part of the bone which 
enters the oral border of the upper jaw behind the premaxilla. The teeth are 
inclined slightly in a posterior direction. Teeth on the premaxilla are confined to 
a Single marginal row and are essentially similar to those on the maxilla but smaller. 
Mandible. The mandible is shown in lateral view in Text-figure 84. It is long, 
very shallow and acutely pointed at the symphysis. The dentary forms the whole of 
the oral border and practically the entire ventral border and has a deeply indented 
posterior edge. The oral margin of the dentary supports numerous irregularly 
placed, small teeth. The teeth are acutely pointed and markedly recurved. 
Towards the posterior end of the dentary the teeth are reduced in number and 
confined to approximately two rows. 
