HISTORICAL REVIEW OF THE PELVCOSAURIA. 1 3 



In the same year appeared Zittel's Grundziige der Paleontologie (135). 

 The scheme of classification is essentially the same as in the Handbuch. 



In 1895 (98) Haeckel published his Systematische Phylogenie der 

 Wirbelthiere in which he gives the following classification: 



Legion Theromore (Theromorpha). 

 Order Theriodontia. 



Suborders Theriodontia, PareosauT'ia , Pelycosauria , Palatosauria . 

 Order Anomodoyiiia. 



Suborders Dicyjiodontia, Oudenodo?itia. 



The suborder Theriodontia is divided into the families Cynodontia 

 {Binaralia)^ Cynodracontia iyUninaralia), Gorgonopsida {Tectinaralia). The 

 first family contains the Clepsydropidee. 



In 1897 Baur and Case (9) published a preliminary account of the skull 

 of DiDidrodon^ in which they showed that the Clepsydropidee possessed the 

 two temporal arches of the Rhynchoceplialia and that they must be placed 

 in that order ; they also showed that the Theroniora could no longer be con- 

 sidered as a good group and that it should be dropped from the literature. 



Cope replied to this paper iu the same 3'ear (82) insisting on the reten- 

 tion of the order Tlicnniiora on other grounds than that of the presence of 

 the Pelycosauria (intending it now to include the pro-mammalian reptiles of 

 all regions), and admitting that the Pelycosauria probably belonged to the 

 Rhynchoceplialia. Since that time the Pelycosmiria have been regarded by 

 almost all authors as belonging in the Rhynchocephalia. Compare Broili's 

 classification below. 



In 1898 (S3), after Cope's death, appeared the second edition of his 

 "Syllabus of Lectures on Vertebrate Paleontology." In this the orders 

 Theroniora, Pelycosauria., and Chclydosaiiria are ranked as equal ; the order 

 Pelycosauria contains the two families Bolosauridee and Clepsydropidee. 

 The order Chelydosauria is new, and contains the genera Otoccelus and 

 Conodectes placed by Cope in the family Otoccelidcs and considered as ances- 

 tral to the turtles. In 1898 Smith- Woodward's "Outlines of Vertebrate 

 Paleontology" (127) placed the "so-called Pelycosaurid^ near the suborder 

 Proterosauria in the order RhyticJiocephalia. 



In the same year Gadow (90) made the Pelycosauria equal to the Theri- 

 odontia as an order in the subclass Theromorpha. 



In 1899 appeared the completed paper by Baur and Case (10), in which 

 they reaffirm the views presented iu the preliminary paper. 



In 1901 (91) Gadow's volume on the Reptiles and Amphibians in the 

 Cambridge Natural History series repeats the views of the first classification. 



In 1902 (100) Hay, in his "Catalogue and Bibliography of the Verte- 

 brata of North America," makes the Pelycosauria an order of equal rank 

 with the Rhynchocephalia. 



