GREGORY: FISH SKULLS 



249 



robust, those in the front being more or less conical and recurved, those in the rear, broad 

 and molariform. The large maxilla and the immense overlapping process of the palatine 

 afford a firm base for the massive premaxilla. The palatine in turn is braced by the stout 

 parethmoid and mesethmoid. In Jrchosargus (Fig. 123) the tendencies already noted 



Archosar^us probatocephalus 



Fig. 123. Archosargus probatocephalus. A. Side view. B. Right premaxilla. Inner view. C. Right and left dentaries. 



Top view. 



attain an extreme expression, so that it would be difficult to find a more strongly built 

 skull. Although any form of Lamarckism as an explanation of such facts is of course un- 

 thinkable, it is worthy of note that the massiveness of these jaws and their supports is 

 apparently in response to the increasing strength of the jaw muscles as well as to the in- 

 creasing toughness of the food, and it is a fact that with this apparatus a sheepshead can 



