ESPECIALLY MYCTOPHOIDS 33 
supported medially by the mesethmoid and vomer. Both the palatine and the ecto- 
pterygoid are furnished with many small conical teeth arranged in a single continuous 
row. 
The exact relationship of the maxilla and premaxilla to one another is uncertain. 
The premaxilla appears to form practically all of the oral edge of the upper jaw, the 
maxilla just entering the gape posteriorly. The oral border of both appears to sup- 
port a continuous row of minute teeth. 
The mandible is long, shallow and acutely pointed anteriorly. The oral edge of 
the dentary bears many small pointed teeth. The articular facet is a shallow semi- 
circular cavity with no trace of a retroarticular process behind it. Along the ventro- 
lateral surface of the dentary a deep groove is found which contained the mandibular 
sensory canal. 
The preoperculum is deep and narrow but characteristically expanded ventrally. 
The anterior edge follows the curved outline of the posterior edge of both hyomandib- 
ular and quadrate. The preoperculum ends dorsally just posterior to the upper 
limit of the crest on the lateral face of the hyomandibular. The near vertical post- 
erior edge of the preoperculum bears a row of prominent tubercles which impart a 
‘toothed’ appearance to the edge. Ventrally the bone is produced into a large 
pt 
d.pt 
v. pt 
sca.cor 
Fic. 14. Apateopholis laniatus (Davis). Pectoral girdle of the left side in lateral view. 
