28 



THE OSTEOLOGY OF THE REPTILES 



figures ( 1 6-1 8) and do not require a detailed description. The den- 

 tary (d) is always present and dentigerous, except in all Chelonia 

 (Fig. 31 B, e), some Anomodontia (Fig. 44 c) and Dromasauria, 

 some Theropoda, and the late Pterosauria (Fig. 71 e), Saphaeosau- 

 rus, etc. 



The coronoid {cor), extending along the inner margin of the teeth 

 from near the symphysis to the hind end of the dentary on the inner 



Fig. 14. Trimerorhachis alleni Case. Temnospondyl skull and mandible: A, right man- 

 dible, inner side; B, the same, outer side; C, D, E, sections of mandible as designated; 

 F, skull and mandible, left side; psp, postsplenial; cor, coronoid; icor, intercoronoid; 

 pcor, precoronoid. 



side, possibly composed of two bones in some of the earliest reptiles 

 (Fig. 18), has been restricted to a place at the posterior end of the 

 dentary in later forms {e. g., Fig. 55 b), and may in some cases be 

 absent. In the Plesiosauria (Fig. 25 a) it still retains its ancient 

 character, even entering into the symphysis in some cases. In the 

 Dinosauria, or some of them at least, it also extends far forward, 

 or there may perhaps be a distinct bone in front, the intercoronoid 



