334 



recent description and figures of the skull, it appears to me to be a larger 

 s2)eciesof Uintatherium than the U. rohustum, l)ut not of a distinct genus. 



The remains, which were first noticed by Professor Marsh and referred to 

 Titanotherium (?) anceps, subsequently to Mastodon anceps, and finally to 

 Tinoceras anceps, I have not seen. I have suspected that perhaps they 

 might pertain to the same animal as that I have described as Uintatlierium 

 rohustum. Should this prove to be the case, as the specific name of anceps 

 is of earliest date, the latter woukl be correctly designated as Uintatherium 

 anceps. 



Professor Marsh regards the Eohasileus s Loxolophodon cornutus, Cope, as 

 pertaining to Tinoceras, probably T. grandis, Marsh, (Am. Jour. Sc. April, 

 1873.) On the other hand Professor Cope refers Dinoceras to Uintatherium, 

 and also includes as synonyms Titanotherium (?) anceps, and therefore Tinoceras, 

 Marsh, (Pr. Am. Phil. Soc. 1873.) Thus the conjoint views of these authors 

 rather favor the idea that all are probably of the same genus. 



Since the article on Uintatherium rohustuin, page 96, was printed, I have 

 attempted a restoration of the skull in Fig. 1, Plate XXVIII, on an enlarged 

 outline taken from Professor Marsh's Fig 1, Plate II, of Dinoceras mirahilis, 

 published in the American Journal of Science for February, J 873. The 

 ci'anial fragment and that of the upper jaw with the last molar tooth are 

 taken from the same skull as the specimens of Fig. 8, Plate XXV, and 

 Fig. 1, Plate XXVl. The canine is from the same specimen as Fig. 1, Plate 

 XXV. 



In the May number of the American Journal of Science for 1873, Pro- 

 fessor Marsh has indicated what he considers to be a new species of Dinoceras 

 with the name of Z>. lucaris. In the account he observes, " From Uintatherium, 

 so far as that genus is at present known, Dinoceras differs in the jJosition of 

 the occipital condyles, in the more anterior position of the posterior horns, 

 and. in the last molar, which lacks the external cone between the two trans- 

 verse ridges, and has a second small tubercle behind the posterior ridge." 

 These characters may, perhaps, together with others more important, point 

 to a different species, but appear hardly sufficient to distinguish a genus. 

 The differences are also more apparent than real ; for instance, the so-called 

 "external cone between the two transverse ridges" of the last molar, as seen 

 in Fig. 7, Plate XXV, is nothing more than a tubercle produced from the 

 basal ridge, might be absent iu another individual, and is actually so in the 

 molar in advance, as seen in Fig. 12 of the same Plate. 



