SYSTEMATIC REVISION 33 



Suborder PAREIASAURIA Seeley. 



1. Skull completely overroofed. 



2. Quadrate concealed. 



3. Temporal region covered by two bones. 



4. External process of the pterygoid present in American forms (unknown in 



Pareiasaurus), with numerous small teeth. 



5. Parasphenoid appears on the lower surface of the skull as a prominent ros- 



trum between the pterygoids. 



6. Ectopterygoid absent. 



7. Tabulare present, often small. 



8. Cheek teeth obtusely conical; one or more than one row in the upper and 



lower jaws. 



9. Hyposphene-hypantrum articulation absent. 



10. Coracoid and procoracoid united with the scapula. 



11. Ischium and pubis broad and plate-like. 



12. Abdominal nbs present or absent. 



Family PARIOTICHIDAE Cope. 



Proc. Am. Phil. Soc., vol. xx, 1883, p. 631. 



Proc. Am. Phil. Soc., vol. xxxiv, 1896, pp. 439 and 442. 



The family Pariotichidce was established by Cope in 1883 to include the genera 

 Partotichus, Pantylus, "and probably Ectocynodon"; it was defined as follows: 

 "Teeth like the Edaphosaurida, but differs from it in the entire overroofing of the 

 temporal fossae." 



The Edaphosaurida was defined as having more than one row of teeth on parts 

 of the jaws. 



In 1896 he gave a tabular statement of the characters of the families of the order 

 Cotylosauria. 



" I. Teeth in a single series. 



Teeth not transversely expanded; vertebral centra with surfaces only ossified; no 



hyposphen Elginida. 



Teeth not transversely expanded; vertebral centra ossified; no hyposphen . . . Pariasauridtt. 

 Teeth with the crovyns transverse to the axis of the jaws; vertebrae ossified and with a 



hyposphen-hypantrum articulation Diadectidtt, 



II. Teeth in more than one series in (one or) both jaws. 



Teeth with cylindric roots; vertebrx ossified Pariotichida." 



The family, as defined by Cope, was based almost entirely upon forms which 

 are in this paper referred to the genus Captorhinus and which are regarded as 

 belonging in a separate family. The characters assigned by Cope to his family 

 Pariotichida are transferred to the new family, Captorhinidee, and the family 

 Pariotichida is redefined. Under the new definition it is made to contain the genera 

 Pariotichus, Isodectes, and the doubtful form Ectocynodon. 



Revised description: 



1. Small; skull rounded anteriorly, flattened, amphibian in appearance. Fine 



sculpture on the bones of the skull. 



2. The basioccipital and basisphenoid united and forming a large plate on the 



base of the skull. 



3. Incisor teeth not enlarged. One or two cheek teeth anterior to the orbit 



sharply larger than the rest. More than one row in the jaws. 

 Only the skull known. 



