422 Lull — Restoration of the Horned Dinosaur Diceraiops. 



backward extent than in other restorations of Ceratopsia. Here 

 we cannot be guided by the form of the mouth in existing 

 reptiles, for none living have the same feeding habits as these 

 dinosaurs. Here the mouth may properly be divided into an 

 anterior prehensile portion, the turtle-like beak, and a posterior 

 masticating portion, the dental armature. In herbivorous 

 mammals the gape only includes the prehensile and never the 

 masticating portion, because of the necessity of muscular cheeks 

 to retain the food in the mouth. The Ceratopsia had a dental 

 apparatus which chopped the food into short lengths, and the 

 pieces, falling outside of the lower jaw, would have been lost 

 had the gape extended backward beyond the beginning of the 

 tooth series. 



Massachusetts Agricultural College, Amherst. 



