1892.] Geology and Paleontology. 411 



which he has applied the names Orohippus, Mesohippus and Miohip- 

 pus, and shows what has been already suspected, that they do not 

 differ from those described and figured many years previously as 

 Hyracotherium for the first named, and Anehitherium for the second 

 and third. He laments the tendency of naturalists to adhere to the 

 appropriate names given by Professor Owen many years ago to the 

 suborders Perissodactyla and Artiodaetyla, and their failure to adopt 

 his own names given to the same divisions, most unnecessarily, many 

 years later. He then repeats as original some generalizations as to 

 the origin of the line of the Periasodactyla, including the horses, 

 which had been long previously made by others, and repeats a new 

 name given to the extinct order Condylarthra, which was intended by 

 him to express an anticipation of its future discovery, rnfortunately 

 this prophecy had been made by others in 1873, and the discovery of 

 the order had been already made and published (1881) before 

 this prophecy of Professor Marsh's was uttered and the speculative 

 name given (1885). He then goes on to state that the genus which 

 first demonstrated the character of this ancestral type as foretold by 

 Cope (1873), which is known as Phenacodus, is the American repre- 

 sentative of Hyracotherium, and was previously named by him 

 Helohyus. Professor Marsh evidently greatly mistakes the characters 

 of Phenacodus, as that genus belongs to a distinct family and order 

 from Hyracotherium. In spite of this assumption as to the ancestry 

 of the horses, Professor Marsh contributes further to the confusion of 

 his writings, by proposing anew name (Hippops) for the speculative 

 ancestral horse. On the strength of his discovery (?) as to the true 

 position of Helohyus, he proposes for it a new family of which it is 

 the type, with a definition which in no way differs from that already 

 given by other authors to the Hyracotheriine division of the family 

 Lophiodontidaa, 1 and which excludes Phenacodus and all other 

 Condylarthra from its limits. It is interesting to observe that Pro- 

 fessor Marsh did not define the alleged genus Helohyus when he pro- 

 posed it, and it is very curious that he does not do so now. He next 

 defines for the first time bis - < hohippida? " ; but the definition does not 

 distinguish whatever it is supposed to embrace, from the hefore-men- 

 tioned " Helohyidte," and we have further confirmation of the preva- 

 lent opinion that this name is also superfluous. On the next page defi- 

 nitions of the alleged genera Eohippus, Helohippus, Orohippus and 

 Epihippus, are given for the first time, i. e. sixteen years after the 

 names were proposed (except Helohippus, which is new). The names 



