58 



A REVISION OF THE COTYLOSAURIA OF NORTH AMERICA 



4.3 mm. high. The crown is distinctly constricted anteroposteriorly in the middle, 

 and though a little worn it is fairly sharp. The fifth tooth is 2.8 mm. by 5 mm., 

 and the sixth tooth is 3.5 mm. by 6 mm. The fifth 

 and sixth teeth are less constricted than the fourth. 



"The dentary is relatively more slender than 

 in Procohphon. There are in the preserved por- 

 tion 5 teeth remaining, and the sockets of 3 more 

 in front. The 5 measure 17 mm. 



"From the shape of the maxillary bone, and 

 from the narrowness of the dentary, it seems prob- 

 able that Thelegnathus had a longer and narrower 

 skull than Procohphon." 



Genus TELERPETON Mantell. 



Mantell, Quart. Journ. Geol. Soc., vol. vni, 1852, p. 100, pt. iv. 

 Boulenger, Proc. Zool. Soc., London, vol. 1, 1904, p. 470. 



Type: In British Museum of Natural History. 



Skull nearly as broad as long, obtusely pointed. 

 Orbits large as in Procolophon, No trace of tem- 

 poral foramina. An epiotic notch not exposing 

 quadrate. No parasphenoid rostrum appearing on 

 the base of the skull. Cheek teeth transversely 

 expanded, bilobate. Intercentra absent. Ribs long 

 and slender. Procoracoid and coracoid distinct 

 from the scapula. Cleithrum absent. Pubis and 

 ischium flat and plate-like. A single element in 

 the proximal row of the tarsus. Phalangeal for- 



1 ■> t A r A Fig. 17. — Outline of Tf/er/K/on. After Boulenger 



rauia 2,3,4, 5, 4. ^^ restorationi b, lateral view of dtuU. 



Suborder PANTYLOSAURIA nov. 



1. Skull completely over-roofed. 



2. Quadrate covered or exposed, without a posterior hook forming a notch 



for the external meatus. 



3. Prosquamosal present. 



4. External process of the pterygoid present and covered with numerous small 



teeth. 



5. Parasphenoid rostrum appearing on the lower surface of the skull. 



6. Ectopterygoid absent. 



7. Tabulate present. 



8. Cheek teeth simple, conical; one or more than one row in each jaw. 



9. 10, II, and 12. Not determinable. 



Family PANTYLIDAE nov. 



Only the skull known. 



1. Slightly larger than the Captorhinida. Skull cordiform. Quadrate not 

 exposed. Surface with a particularly close, reticulate sculpture. 



2. Median incisors very slightly larger than the others. Cheek teeth in the 

 form of blunt, swollen cones; the second or third larger than the others. Posterior 

 cheek teeth small. 



3. More than one row of teeth in the jaws. 



