CLASSIFICATION OF THK THERIODONTIA. 



Text-fioure 21. 



71 



Series of dvawiiigs of the i-iglit lateral aspect of Pelj'cosanr skulls, 

 reduced to the same length. 

 A. Varanosaurus acutirostris Broili, restored froui the tjqie-sliull in Munich, partly 

 after Broili. B. Beiopens leptocepJialus Cope, restored from the type-skull 

 in the American Museum. C. Sphenacodon ferox Marsh, after Williston. 

 D, JJimetrodon gigas Case, from a photograph published by Case. 



