36 A REVISION OF THE COTYLOSAURIA OF NORTH AMERICA 



Original description: "Parietal and frontal regions flat, the latter joined to the 

 maxillary by a rectangular canthus. Interorbital region wide, equal to the diameter 

 of the orbit. Sculpture of vertex in longitudinal series of pits of considerable 

 irregularity. There are ten or twelve such rows between the orbits. The crowns 

 of the teeth are obtuse, and their surface smooth. 



"Measurements. 



"Interorbital width of skull 0.009 



Width between prefrontal borders 014 



Depth of facial plate of maxillary 007 



Depth of ramus mandibuli at orbit 006 



Depth of ramus mandibuli near end 003 



Length of short maxillary tooth 0015 



Length of long maxillary tooth 0030 



Width of long maxillary tooth 0015 



"The skull of this species is about as large as that of Heloderma suspectum." 

 Revised description of the genus and species: The condition of this specimen 

 makes it impossible to give a comparative list of characters; it is a mere fragment 

 of a skull in very poor condition. The shape of the fragment 

 indicates that the skull was wider than that of Pariotichus, and 

 sculptured in a very different pattern. Between the orbits, the only 

 place where the sculpture is preserved, the lines are arranged in a 

 very regular basket pattern (see fig. 10). The character of the 

 teeth appears to be quite the same as in Pariotichus. Cope con- 



sidered the enlarged cheek tooth to be farther forward than in 



Fig. 10.— Top of skull of P^riotichus and called it a canine, but this does not seem at all 



E.trdinatus. XI. Type certain. 



No. 4345 Am. us. This genus and species is, without doubt, different from both 



Pariotichus and Isodectes, but the specimen is so imperfectly preserved as to be 

 almost indeterminate. It is retained provisionally only. 



Genus ISODECTES Cope. 



Pariotichus Cope, Proc. Am. Phil. Soc., vol. xx, 1883, p. 630. 

 Pariotichus Cope, Trans. Am. Phil. Soc., vol. xvil, 1892, p. 14, fig. 3, pi. I. 

 Isodectes Cope, Proc. Am. Phil. Soc., vol. xxxiv, 1896, p. 442. 

 Isodectes Cope, Proc. Am. Phil. Soc., vol. xxxv, 1897, p. 88, fig. 3, pi. m. 



Type: An imperfect skull. No. 4329 Am. Mas. Nat. Hist. Cope Coll. From 

 Texas. 



Original description: This skull was originally referred to the genus Pariotichus 

 (see the description of Isodectes megalops following) and lepeatedly described as 

 such, but in a tabular statement of the genera of the Partottchidce published in 1896 

 Cope gave the new name with the following characters: "External nostrils lateral. 

 Palatal and splenial teeth with compressed crowns. Teeth equal, acute." 



Isodectes megalops Cope. 



Pariotichus megalops Cope, Proc. Am. Phil. Soc., vol. XX, 1883, p. 630. 

 Pariotichus megalops Cope, Trans. Am. Phil. Soc., vol. xvil, 1892, p. 25. 

 Isodectes megalops Cope, Proc. Am. PhU. Soc., vol. xxxiv, 1896, p. 442. 



Type: Same as the genus. 



Original description: "This reptile is known to me from a nearly complete, 

 somewhat distorted cranium. A thin layer of matrix conceals the greater number 



