HISTORICAL REVIEW OF THE PELYCOSAURIA. 15 



In 1903 (18) Broom published his classification of the Theriodonts 

 and related forms. Somewhat condensed, the scheme is as follows: 



Rhynchocephaloid Orders. Theromorous Orders. 



Order Procolopho^iia. Order Pareiasauria. 



Family Procolophonidee. Family Pareiasauridcs . 



Genus Procolophonia. PariotichidcB . 



Order Pelycosmiria. Diadedidce. 



Family Clepsydropida. Order Therocephalia. 



Genus Clepsydrops. Family Scylacosaurida . 



Dimetrodon. Aehirosatiridce. 



Naosaurus. Ictidosuchidce. 



Embolophorus. Titanostichidts. 



fGorgonopsidcE . 



Order Theriodo7itia. 



Family Lycosauridm . 

 Galesaurida . 

 Goniphognathida . 



Order Anomodo7itia. 



Family Endothiodontida . 

 Dicyn odon tidce . 

 LystrosauridcB. 

 Cistecephalida . 



In 1904 (13) Broili, in his work on the Permian Reptiles and Stego- 

 cephalians from the Texas region, revives the order Theromora (using the 

 preoccupied name Theromorpha). His classification is as follows: 



Order Rhynchocephalia. 



Family Paterosauridce . 

 Genus Lysorophus . 

 Order Theromorpha. 



Suborder Coiylosauria Cope {Pareiasauria Owen). 



Families Pareiasauridce , Otoccelida, Diadectida:, PariotichidcB. 

 Suborder Pelycosaiiria Cope (Theriodontia Seeley). 

 Families Clepsydropidce , ?Bolosaurida. 



It will be observed that the genus Lysorophus commonly placed among 

 the Pelycosauria is the only one considered as belonging to the Rhyncho- 

 cephalia^ and is placed in a new family. This family is considered as per- 

 haps the most primitive of all the reptiles. 



Boulenger in 1904 (16) divided the reptiles into two great groups, the 

 Reptilia Theromora^ derived directly from the Labyrinthodontia^ and the 

 Reptilia Herpetofnorpha^ derived from the Microsauria. He places the 

 Pelycosauria as a side branch of the Rhynchocephalia^ of ordinal rank. 



