Marsh — New Reptiles from the Laramie Formation. 451 



Various vertebrae found at the same localities may be re- 

 ferred to this species. They are proccelian, with the cup 

 and ball transverse, and oblique. These are all without the 

 zygosphene articulation. 



Figure 2. — Maxillary of Chamois segnis, Marsh ; outer view. 

 Figure 3. — The same bone ; inner view. Twice natural size. 



The remains of the species here described are all from the 

 Laramie of Wyoming. 



Iguanavus teres, sp. nov. 



Another Lacertilian, much smaller than the above, left its 

 remains in the same horizon. The specimens best preserved 

 are vertebras, which agree in general form of the centra with 

 those just described, but possess the zygosphene articulation. 

 They .are about the size of the Ophidian vertebra above 

 described, but may readily be distinguished by the oblique 

 and transversely expanded articular faces, and by the smooth 

 under surface of the centrum. The type specimens are all 

 from the Laramie of Wyoming. 



Ornithomimus sedens, sp. nov. 



The remarkable Dinosaurs described by the writer, and 

 referred to the present genus, representing a distinct family, 

 were mainly from fragmentary remains, but differed widely 

 from all forms then known.* Since then explorations in the 

 same horizon further north have brought to light various other 

 specimens, which prove the group to be of great interest, but 

 make it probable that they should be referred, not to the 

 Omithopoda, but to the Theropoda. 



The present species is based upon the nearly complete 

 pelvis, with various vertebrae, and some other parts of the 

 skeleton. The most striking feature of the pelvis is the fact, 

 that the ilium, ischium, and pubis are firmly coossified with 

 each other, as in recent birds. This character has been observed 



*This Journal, vol. xxxix, p. 84, January, 1890. 



