GREGORY: FISH SKULLS 



217 



from below (Figs. 96, 97). The suspensorium, including the symplectic, is produced far 

 forward. The pre- and inter-opercula are also inv^olved in the forward growth of the 

 suspensorium. 



More in detail, the mouth is more or less widened transversely, is bordered by small 

 teeth usually simple but sometimes with bifid crowns; teeth borne by the premaxillae and 

 dentaries, maxillae excluded from gape in the manner characteristic of spiny-rayed fishes. 

 The premaxillae lie in an anterior lip-fold which also includes the dentigerous border of the 



sphot 



'^ pa .■ epiot 



Belonesox belizanus 



Fig. 96. A. Fundulus. Side view. B. BAonesox belizanus. Side view. 



dentaries, while the maxillae lie in a postero-jateral lip-fold which overlaps the dentary and 

 is associated with the lacrymal and cheek-folds. A ligament passes from the lower outer 

 part of the maxilla obliquely upward and forward to the lower outer end of the premaxilla. 

 The tendon of the superficial layer of the adductor mandibulae muscle is inserted on the 

 back of the lower outer part of the maxilla, nearly opposite the tendon that runs to the 



