24 



F. von Huene — Order Thecodontia. 



structures, but the evidence is not yet complete enough 

 to do this. Further, it might be noted that "Rutiodon" 

 manhattanensis probably does not belong to this genus 

 but to another. 



In a paper still in press 20 an extensive discussion is 

 given of the history of the Parasuchia, and in another 

 a general view of the Thecodontia. 



The writer holds 13 that the Pseudosuchia give rise to 

 the Archosauria. The reasons for this need not be 

 repeated here. From forms probably nearly related to 

 the Ornithosuchidse, the Ornithischia and the Aves prob- 

 ably arose through adaptations and the Pterosauria not 

 very far from them. The Crocodilia also probably came 

 from that part of the stem. But the Saurischia the 

 writer takes to be an offshoot of the very earliest Pseudo- 

 suchians in the most ancient Trias sic time. 



Capfo- 

 rhinidae 



/^p^oJiTTac^e Acrosaundcte jSphenoc/orttictae 

 <$> ■& £copodjLia,__ 



der''*'**^ 4.Kfl 



P<seudosuc/iia 



■ In 1920 17 the writer expressed the opinion that the 

 Khynchocephalia (with the taxonomic rank of an order) 

 are descendants of the same root as the Thecodontia. 

 If that is true, it would be easy to understand why so 

 many characters are common to both phyla. From this 

 viewpoint, the Gnathodontidas (Howesia, Mesosuclius, 

 Br achy rhino don, Polysphenodon and probably Eifelosau- 

 rus) would form the most primitive family of the Rhyn- 

 chocephalia. The contemporaneous family Rhyncho- 

 sauridse (Ilhynchosaurus , Hyperodapedon and Sten- 

 ometopon) is little more specialized. The stem of the 

 Rhynchocephalia is represented in later times by the 

 AcrosauridsB in the Upper Jurassic and by the Tertiary 

 and present Sphenodontidas. In the Upper Jurassic the 



