58 On Reptilian Remains from the Trias of Elgin. [April 29, 



III. ORNITHOSUCHUS WOODWARDI, E. T. Newton. 



The specimen on which this species was founded by Mr. Newton in 

 1894, indicated a reptile about 2 feet long. Specimens more than 

 twice as large are now described, and afford much information on 

 points which remained obscure. Chicles were present, large and 

 widely expanded at their inner extremity, where they overlapped the 

 inter-clavicle. A plastron, or system of abdominal ribs, was also 

 present, resembling very closely that of Sphenodon, each segment being 

 formed of a median angulate piece to which a lateral limb is attached, 

 the segments, however, being much more numerous and closer together 

 than in the New Zealand reptile. 



The presence of clavicles and of a plastron show that Ornitfwsuchu* 

 cannot be included among the Dinosaurs, as originally suggested, but 

 must be placed in the Order Thecodontia, of Owen, which contains 

 Belodon and Aetosaurus. The Thecodontia should be kept distinct from 

 the Crocodilia or Emydosauria; they agree with the latter, the 

 Dinosauria and the Pelycosauria, to which they are very closely 

 related, and differ from the Rhynchocephalia, in the truly thecodont 

 dentition; they agree with the Rhynchocephalia and Pelycosatiria r 

 and differ from the Emydosauria and Dinosauria, in the presence of 

 clavicles, whilst they show close resemblance to the Rhynchocephalia 

 proper in the structure of the plastron. The presence of clavicles 

 and the condition of the pelvis, in which the pubis enters the 

 acetubulum, together with other characters showing greater generali- 

 sation, afford ample justification for the separation of the Thecodontia 

 or Parasuchia, as a group of ordinal rank, from the Emydosauria. 

 The author also expresses the opinion that precision in the definition 

 of the higher group of reptiles would gain much by the Order 

 Dinosauria being restricted to the carnivorous, truly thecodont forms, 

 the others deserving to form an equivalent Order under the name 

 of Orthopoda, Cope (Predentata, Marsh, Ornithischia, Seeley). 



