GREGORY: FISH SKULLS 



415 



insertion to part of the adductor muscles. In the oldest ganoids (pp. 112) there was a 

 vertical wall above the palatine and pterygoid which must have greatly strengthened the 

 palato-quadrate arch and protected the neurocranium. 



Adaptive Radiation of the Mouth and its Parts. — The leading modifications of the bony 

 parts of the mouth and throat have conditioned the size, the position, and the direction of 



Mdi/.op Mtrap 



M.leir.arc.pal^ 

 M. ad.paly.^ 



Ad'3fi 



^toAo:>) Adz 

 (■ins) 



Adz 



Fig. 285. Relations of the Jaw Muscles and their Tendons. After Vetter. A. Pike {Esox luctus) after removal of super- 

 ficial layers Ai, Aj. B. Typical percoid (Percafluviatilis) after removal of superficial portion (Ai) of the adductor mandibula. 



The main tendon of Ai inserts on the inner side of the maxilla. The tendon of Ai inserts on the inner side of the coronoid 

 process of the mandible. The tendon of A. insert* on the inner side of the mandible. Au nearly fills the inner side of the man- 

 dible; its tendon joins that of Ai. 



