146 F. R. von Huene — Dinosaurs not a Natural Order. 



the Sauriscliia and at the same time show the higher degree of 

 adaptation and specialization of the former group. Already in 

 1908 I stated that we do not know any Ornithischia in the 

 same degree of primitiveness which we know in the oldest 

 Sauriscliia. 



In the vertebral column, Sauriscliia of the highest degree of 

 specialization do not possess ossified tendons as do all bipedal 

 Ornithischia, even the relatively primitive Hypsilophodon. 

 This must be due to a different manner of locomotion and 

 of feeding. The different kind of motion must be referable 

 to the same cause as the transformation of the pelvis and its 

 stronger fixation at the vertebral column. Also, abdominal 

 ribs are not yet known in Ornithischia, but they do occur in 

 Saurischia, even in some of the latest forms. 



In a recent paper the writer has tried to demonstrate that 

 the Saurischia and the Ornithischia came from the Pseudosuchia, 

 the former directly from their most primitive representatives 

 by minor specializations, the latter from more specialized 

 Pseudosuchians by a stage of bipedal hopping creatures, in 

 which the pelvis became adapted to this new locomotion by 

 retroversion of the pubis and development of a praepubis. 

 (From this stage — as the writer suggests — the birds also were 

 formed by becoming climbers on trees, then becoming adapted 

 to flying by means of expansions of the skin known as patagia, 

 subsequently acquiring feathers and ultimately learning true 

 flight. These are Abel's ideas combined with those of the 

 present writer.) 



In 1908 the writer showed that the Sauropoda have 

 developed from the Plateosauridse, an opinion he stills sustains 

 though some minor changes in the knowledge of the Saurischia 

 have taken place. He now makes two large suborders within 

 the Saurischia : Coelurosanria and Pachypodosauria. In the 

 former there are four families : Hallopoda, Podokesauridae 

 (Podokesaurus, Procompsognathus, Saltopus, Coelophysis and 

 Tanystrophseus), Compsognathidae and Coeluridae (including 

 Ornithomimus). The second suborder would again comprise 

 two lines of development, one leading from Thecodontosaurus 

 to the Plateosauridae and Sauropoda, the other from Palaeo- 

 saurns to the Megalosauridse. For further information on this 

 subject the writer refers to some of his latest papers : "Beitrage 

 zur Geschichte der Archosaurier," Geol. u. Palaeont. AbhandL, 

 vol. 13 (17), H. 1, 1914; "IJeber die Zweistammigkeit der 

 Dinosaurier, mit Beitragen zur Kenntnis einigen Schiidel," 

 N. Jahrb. f. Min., etc., JBeil. Bd. 37, 1914, pp. 577-589 ; "Das 

 natiirliche Svstem der Saurischia," Centralbl. f. Min., etc., 1914, 

 pp. 154-158'. 



Tubingen, March 10, 1914. 



