GEOLOGICAL SUEVEY OF THE TERRITORIES. 591 



This large ungulate was found in a stratum below those of the Green 

 Eiver group of Hayden, or in the lower beds of that series, near Black 

 Buttes, Wyoming. 



It is not certain that the last-named species of Bathmodon does not be- 

 longto this genus. All three are distinct from the M. armatus, the latter, 

 though young, being considerably larger than Bathmodon latipes. 



PEEISSODACTYLA. 



PAL^OSYOPS, Leidy. 



Hayden's Geological Survey of Montana, 1871, page 358 ; (?) Proceedings Academy 

 Natural Sciences, Philadelphia, 1871, p. 118. Limnohyus Marsh, American Journal 

 Science and Arts^ 1872, p. 124. 



This genus has been partially described by Professor Leidy, and much 

 light is thrown on its structure by the materials obtained by the survey 

 of 1872. As pointed out by Leidy, this genus differs from Palceotherium 

 in the isolation of the internal cones of the superior molars from the ex- 

 ternal longitudinal crescentoid crests, and in the presence of but one 

 inner tubercle on the last three premolars instead of two. There is but 

 one internal cone on the last superior molar, I^umber I. 3, C. 1, P. M. 

 4, M. 3. Number of inferior molars similar; true molars, with four 

 acute tubercles alternating in pairs and connected by oblique crests, 

 which thus form two V's, with their apices exterior. The last molar 

 adds a fifth posterior tubercle. The last premolar lacks the posterior 

 inner tubercle. The second and third have but one, the outer series 

 of tubercles, — and the first is compressed. The canines are separated 

 by a slight interval from the premolars, and are in continuity with the 

 incisors. 



The dental characters are generically identical with those of Titano- 

 therium, Leidy, which must be referred to the Perissodactyla, and not to 

 the Artiodactyla, as left by Leidy in the " Extinct Mammalian Fauna of 

 Dakota and Nebraska," though originally referred by him to this order. 



The species originally named by Leidy Palceosyops paludosus belongs 

 to the succeeding genus, Limnohyus, Leidy. He afterward included 

 species of the present genus in it, and in so doing first characterized the 

 genus. Hence I agree with him in retaining the generic name for the 

 latter, and not the former, as is done by Marsh. The original form was 

 not characterized generically, a brief specific description only being 

 given. 



Pal^osyops l^videns, Cope. 



LimnoJixjus Icevidens, Cope ; Proceedings American Philosophical Society, 1873 ; pub- 

 lisJied January 31. PalcBosi/ops paludosiis, Leidy ; Hayden's Survey of Montana, 1871, 

 p. 359, not Proceedings Academy Natural Sciences, Philadelphia, 1870, p. 113. 



A species about the size of the Anoplothernim commune, Guv., and inter- 

 mediate between the Palceotherium magnum and P. medium. It is con- 

 siderably larger than the existing tapirs, and was one of the most 

 abundant of the quadrupeds of the Eocene of North America. 



It is chiefly represented by a nearly complete cranium with dentition, 

 from Bitter Creek, and a cranium lacking the posterior part of one side 

 and the lower jaw, from Cottonwood Creek. The molars have the gen- 

 eral form of those of L. rohustus, but the second superior premolar has 

 but one outer tubercle. The cingula are much less developed than in 

 that species ; those between the inner cones of the molars being entirely 

 absent. These cones are low, and, with the rest of the crowns of all the 



