218 



TRANSACTIONS OF THE AMERICAN PHILOSOPHICAL SOCIETY 



premaxilla. When the mandible is depressed by the throat muscles the premaxilla is 

 drawn downward and the maxillo-premaxillary ligament also pulls the maxilla downward 

 and forward. When the adductor mandibulse muscles begin to contract the mandible is 

 drawn upward, the maxillae backward, the premaxillse backward and upward. The palatine 

 also is movable, permitting the movement of the maxilla (Starks, 1926a, p. 205). 



Belonesox (Figs. 96B, 97C) is essentially a small predatory poeciliid with much enlarged 



Fig. 97. A. Orestias sp. Top view. B. Fundutus sp. Top view. C. Belonesox. Top view. 



