26 UPPER CRETACEOUS TELEOSTS 
dibular nerve passed. Within the bone the nerve divided ; the opercular nerve 
left through a small foramen lateral to the opercular process ; the hyoidean and 
mandibular nerves left through a large foramen in the angle between the base of the 
opercular process and the lateral crest. There is a possibility that a second branch of 
the mandibular nerve passed through a foramen on the lateral face of the hyo- 
mandibular near to the ventral extremity. 
op 
den 
art pop 
ang 1op sop 
; 5SOmm ; g.sym 
Fic. 10. Apateodus striatus Woodward. MHyopalatine and opercular bones and mandible 
of the right side in medial view. From the collection of the Institute of Geological 
Sciences, number 26241. 
The quadrate is large, triangular and has a prominent transversely arranged, mesi- 
ally constricted condyle. The groove on the medial face of the quadrate which 
housed the symplectic is long and shallow and terminates just above the condyle. 
Posterior to the symplectic groove the postero-dorsal part of the quadrate is emarg- 
inated. Anteriorly the quadrate is flattened and extends forwards over the lateral 
face of the posterior end of the ectopterygoid. On the medial face the ectopterygoid 
extends back almost as far as the condyle. 
The metapterygoid is a thin membranous bone overlying the edges of both the 
hyomandibular and the endopterygoid but not reaching the dorsal region of the 
quadrate. Laterally the metapterygoid bears a slight antero-posteriorly orientated 
crest which forms the leading edge of the metapterygoid ventrally. 
The ectopterygoid is laterally compressed posteriorly, but widens anteriorly where 
it supports teeth. Anteriorly the ectopterygoid joins the palatine, and the medial 
edge of the ectopterygoid supports the endopterygoid. There are seven large teeth 
