OSTEOLOGY OF CAENIVOROTJS DINOSAURS. 131 



The family Ornithomimidae may now be characterized as follows: 



Skull relatively small and edentulous. Pelvic elements coalesced; cervical 

 ribs coossified to vertebrae, as in birds. 



Generic characters. — Fore limbs slender and elongate, with three digits, pro- 

 vided with long, slightly recurved terminal phalanges. Femur shorter ' than tibia; 

 pes with three digits, with or without vestigal fifth digit; distal caudals having 

 an anterior rod-like elongation of the prezygapophyses. 



Below is given a list of the species assigned to the genus Ornithomimus, the 

 location of the type, its catalogue number, and the geological formation from 

 wliich the type specimen was obtained : 



Ornithomimus velox Marsh, 1890, Cat. No. 542, 548, Yale University Museum, 

 Denver Foi-matiou, Upper Cretaceous. 



Ornithomimus tenuis, 1890, Cat. No. 5814, U.S.N.M. Judith River forma- 

 tion. Upper Cretaceous. 



Ornithomimus f/randis=I)einodon (?) grandis (Marsh), 1890. Type lost. 

 Eagle formation, Upper Cretaceous. 



Ornithomimus sedens Marsh, 1892, Cat. No. 4736, U.S.N.M., Lance formation, 

 Upper Cretaceous. 



Oi-nithomimus minutus Marsh. Type lost. Denver (?) formation. Upper 

 Cretaceous. 



Ornithomimus altus Lambe, 1902, Cat. No. 930, Ottawa Museum, Belly River 

 formation. Upper Cretaceous. 



Ornithomimus qffinis, new species, Cat. Nos. 5704, 5684, 5453, 5652, 6108, 

 5703, 8456, and 6107, U.S.N.M., Arundel formation, Lower Cretaceous. 



ORNITHOMIMUS SEDENS Marsh. 1892. 



Plate 35, fig. 1. * 



Ornithomimus sedens Marsh, O. C, Amer. Journ. Sci., ser. 3, vol. 43, 1892, p. 451: Sixteenth Ann. 

 Rapt. U. S. Geol. Surv., pt. 1, 1896, p. 205, figs. 49-52.— Hay, 0. P., B-ull. No. 179, U.S.Geol. 

 Surv., 1901, p. 494.— NopcsA, P. Baron, Foldtani Kozlony, Budapest, vol.31, 1901, p. 201.— 

 OsBORN,H. F.,Contrib. to Canadian Paleontology, vol.3, pt. 2, p. 13, 1902. — Merrill, G. P., 

 Cat. of Vertebrate Fossils, U. S. Nat. Mus., pt. 2, 1907, p. 74.— Bowen, C. F., U. S. Geol. 

 Survey, Professional Paper 90 — I, p. 134, 1915. 



Type material. — No. 4736, LT.S.N.M. Consists of the sacrum and 12 caudals 

 in series, 6 chevrons, portions of both ilia and pubes, and both ischia. Collected 

 by J. B. Hatcher and A. E. Sullins, 1891. 



Type locality. — Alkali Creek, Niobrara County (formerly Converse County), 

 Wyoming. 



Horizon. — Lance formation, Upper Cretaceous. 



The description of the type specimen of Ornithomimus sedens by Professor Marsh 

 is as follows: 



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 

 hitherto among dinosaurs only in Ceratosaurus, described by the writer from the Jurassic of Wyoming.' 



1 Not longer, as stated by Marsh in liis diagnosis of the genus, p. 240, Dinosaurs of North -America. 



2 A mistake; the specimen is from Colorado. 



