18 



Deinodon should be applied to it.* This name was securely founded on megalosaurian 

 teeth, and those first mentioned in both Leidy's descriptions and first figured in his 

 memoir on the Judith Eiver vertebrates must be regarded as valid types irrespective of 

 the following facts : (1) that Leidy expressed some uncertainty as to his separation of 

 Deinodon from the Jurassic genus MegaJosaurus, (2) that he associated with the types a 

 number of large serrate incisor teeth, truncate posteriorly, which probably belong with 

 Deinodon, (3) also smaller non-serrate teeth, also truncate posteriorly, which certainly do 

 not belong with Deinodon, (4) that he subsequently selected the two latter (2 and 3) as 

 the types of Aublysodon. 



The Cretaceous carnivorous dinosaur of the Judith River beds should, therefore, be 

 named Deinodon. Belonging to this is the type species D. horridus, Leidy ; probably also 

 the species D. cristatus. Cope and D. IcEvifrons, Cope, from Montana. To Dnjptosaurus, on 

 the other hand, belongs the large Upper Cretaceous carnivore D. incrassalun, Cope, from 

 the Edmonton series of Alberta. 



Family Ornithomimida. Mr. Lambe's discovery of additional remains of Or^iithomimus 

 in the Belly River series, as represented by a very large new species, is of great interest. 

 Mr. Hatcher states that he found Marsh's type of this genus, consisting of a foot and a 

 portion of a limb, on Cow island, Missouri river, at a level which he estimates from 

 1500 to 1600 feet below the summit of the Judith River beds, and 500 to 600 feet below 

 the level of Marsh's type of Ccratops montanus. 



Ornithomimus alius is probably a successor of a comparatively small and lightly built 

 dinosaur recently discovered by the American Museum parties in the Como beds of 

 Wyoming.** This Upper Jurassic animal measures 7 feet 4 inches from the tip of its. 

 premaxillaries to the tip of its tail. Estimated bj^ the comparative size of its metapodials 

 the Mid-Cretaceous O. alius was 22 feet in length with an extremely long and slender 

 tail. The entire absence of vertical spines or neurapophyses in the mid-portion of the 

 tail indicates that it was exclusively terrestrial in its habits and adapted to very rapid 

 running. The resemblance to its Jurassic ancestor is especially striking in the greatly 

 elongated zygapophyses of the caudal vertebrro which replace the neural spines and in 

 the lateral compression of the terminal phalanges of the manus. Ornithomimus is more 

 progressive than its supposed ancestor, in the development of cursorial rather than 

 prehensile phalanges in the pes, these elements having nearly lost the recurved megalo- 

 sauroid structure. 



The teeth of this genus are not known ; but compai'isou with its .Jurassic prototype 

 gives ground for believing, as suggested by Mr. Lambe, that the smaller teeth described 

 by Leidy as Aublysodon may belong in the anterior part of the jaw ; this genus, however, 

 is by some considered invalid because based in part upon teeth belonging properly to 

 Deinodon. 



DiNOSAXJRiA : (Ornithopoda) Iguanodontia. One of the distinguishing features 

 of the Belly River fauna is the great number and variety of the Iguanodouts. Of the 



* Dr. 0. P. Hay (Amer. Geologist, xxiv, 1S99, p. .346) is of the opinion that Cope was justified in rejecting the 

 name Deinodon. 



**It will shortly be described by the present writer in a biiUetiu of the American Museum. 



